Master's thesis of Engineering: Application of ceramic Ultrafiltration/Reverse Osmosis membranes and enhanced membrane bioreactor for the reuse of car wash wastewater

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

A thesis submitted in fulfilment of the requirements for the degree of

Master of Engineering

SHAMIMA MOAZZEM

School of Engineering

College of Science, Engineering and Health

RMIT University

June 2017

Bachelor in Civil Engineering, Bangladesh University of Engineering and Technology (BUET)

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

DECLARATION OF ORIGINALITY

I certify that except where due acknowledgement has been made, the work is that of the author alone; the work has not been submitted previously, in whole or in part, to qualify for any other academic award; the content of the thesis is the result of work which has been carried out since the official commencement date of the approved research program; any editorial work, paid or unpaid, carried out by a third party is acknowledged; and, ethics procedures and guidelines have been followed.

Shamima Moazzem

June 2017

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

ACKNOWLEDGEMENTS

I am delighted to acknowledge those who have encouraged me and contributed in many ways

during my progress and towards the completion of this research.

Firstly, I would like to express my sincere gratitude to my Principal Supervisor Prof. Veeriah

Jegatheesan for his continuous guidance, assistance, and encouragements during this research.

I deeply appreciate his effort in providing me the opportunity to have this learning experience.

I would also like to show my generous appreciation to my Associate Supervisor Prof. Felicity

Roddick and Dr. Linhua Fan for their valuable suggestions and guidance throughout this

research.

I acknowledge the support I have received for my research through the provision of an

Australian Government Research Training Program Scholarship. I would like to express my

special thanks to Peg Gee Chang, Cameron Crombie, Sandro Longano, Mike Allan for

providing guidance and support in various ways to conduct my laboratory experiments. I want

to express my special thanks to Cameron Crombie, senior technical officer for his help for

making the membrane module which was the key element of my experiment.

I would also like to acknowledge Harish Ravishankar and Susanthi Liyanaarachchi who were

mentoring and providing support in various ways during my time at RMIT University. I am

also grateful to Li Shu, Shruti Sakarkar, Jamie Wills, Zubayeda Zahan and Nusrat Rezwana

Binte Razzak for their kind help during my research.

Above all, I would like to express my special thanks and appreciation to my husband

Mohammad Taufiqul Arif, my son Aayan Tausiq Arif, my parents and parents-in-law for their

patience, understanding, sacrifices and encouragements during this research.

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

ABSTRACT

The most convenient way of transportation is car and the use of car is increasing to improve

our daily activities. According to the Motor Vehicle Census (MVC) in 2016, there are 18.4

million registered motor vehicles in Australia. The demand of car washing is also increasing

for better maintenance of these cars. But the wastewater generated from this car wash centers

is a major concern for the environment as it contains different type of pollutants such as

petroleum hydrocarbon waste (gasoline, diesel and motor oil), heavy metals (such as copper,

lead and zinc), nutrients (phosphorus and nitrogen), surfactants and suspended solids,

microorganisms, sand and dust. A literature survey showed that over 35 billion litres of

contaminated wastewater are being disposed of rather than recycled from 10,000 car wash

centers in Australia every year. Therefore, appropriate treatment processes are required to treat

car wash wastewater which enables us to reuse the treated water at car wash facilities and

efficiently isolate pollutants from the wastewater.

Past research studies have used different treatment technology comprising of conventional

treatment and membrane based treatment. The aim of this study is to develop a treatment system

which is cost effective, have a small footprint (with respect to space) and produce high-quality

recycled water. After critically evaluating the available literature and previous studies, two

membrane based technologies were selected here. The first treatment system comprising of

coagulation-flocculation, sand filtration, ceramic ultrafiltration membrane and reverse osmosis

were set-up in the Laboratory, and the treated water qualities were analyzed to evaluate the

removal efficiency of various parameters at every step.

An Enhanced Membrane Bioreactor (eMBR) was selected as a second treatment system in this

research. The eMBR system comprised of anaerobic and anoxic bioreactors followed by an

aerobic membrane bioreactor as well as an ultraviolet (UV) disinfection unit which are a

combination of biological treatment, membrane separation, and physical treatment processes.

This treatment systems were set-up in the laboratory and ran for 17 months. In the first stage of

experiment, synthetic wastewater was used to acclimatize the microorganisms present in all

three reactors (anaerobic, anoxic and aerobic membrane bioreactor). In the second stage,

different percentage of car wash wastewater was introduced with the synthetic wastewater. The

permeate water quality was analyzed to evaluate the removal efficiency of various parameters.

The short term critical flux tests were conducted to determine the fouling characteristics of the

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Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

membrane. In the final stage, the hydraulic retention time (HRT) of the system was reduced to

find out the optimum operating condition. Moreover, the performances of the first and second

treatment systems were compared based on the recycled water quality. It was found from the

experimental results that both treatment systems were able to produce high-quality recycled

water which can be reused for washing the cars in a car wash center. However, eMBR was able

to produce higher-quality permeate compare to first treatment system (in the first treatment

system the removal efficiencies of COD, turbidity and total nitrogen were 96.1, 99.9 and 74.4%,

respectively and in the eMBR they were 99.6, 99.9 and 66.3%, respectively). Moreover, first

treatment system produced a significant amount of waste whereas eMBR produced no

disposable waste during 17 months of operation.

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

To my parents

K. Moazzem Hossain and Shahan Ara Begum

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

LIST OF PUBLICATIONS

Conference

• Shamima Moazzem, Susanthi Liyanaarachchi, Linhua Fan, Felicity Roddick, Jega Jegatheesan, Recycling car wash wastewater using ceramic membrane ultrafiltration, International Membrane Science And Technology Conference – 9th IMSTEC 2016, 5-8 December 2016, in Adelaide, Australia.

Journal

• Shamima Moazzem, Jamie Wills, Linhua Fan, Felicity Roddick, Jega Jegatheesan (in preparation), Performance of ultrafiltration ceramic membrane in treating car wash wastewater for the purpose of recycling.

• Shamima Moazzem, Harish Ravishankar, Linhua Fan, Felicity Roddick, Jega Jegatheesan (in preparation), Performance of Enhanced Membrane Bioreactor in treating car wash wastewater for the purpose of recycling.

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

DECLARATION OF ORIGINALITY ............................................................................................................. I

ACKNOWLEDGEMENTS .............................................................................................................................. II

ABSTRACT ..................................................................................................................................................... III

LIST OF PUBLICATIONS ............................................................................................................................. VI

TABLE OF CONTENTS ................................................................................................................................ VII

LIST OF FIGURES .......................................................................................................................................... X

LIST OF TABLES .......................................................................................................................................... XII

LIST OF ABBREVIATIONS ........................................................................................................................ XIV

COPYRIGHT STATEMENT ........................................................................................................................ XV

CHAPTER 1 ...................................................................................................................................................... 1

1 INTRODUCTION .................................................................................................................................... 1

BACKGROUND ................................................................................................................................... 1 DESCRIPTION OF THE PROPOSED RESEARCH .................................................................................... 1 AIM AND OBJECTIVE ......................................................................................................................... 2 RESEARCH QUESTIONS ..................................................................................................................... 3 SCOPE OF THE RESEARCH ................................................................................................................. 3 EXPECTED DELIVERABLES ................................................................................................................ 3 RATIONALE OF THE RESEARCH ........................................................................................................ 3 Importance of undertaking this research .................................................................................. 4 Benefit of this research to the Community ................................................................................ 4 Significance of this Project......................................................................................................... 5 THESIS OUTLINE ................................................................................................................................ 5 CONCLUSIONS ................................................................................................................................... 6

CHAPTER 2 ...................................................................................................................................................... 7

2 LITERATURE REVIEW ........................................................................................................................ 7

INTRODUCTION ................................................................................................................................. 7 TYPES OF CAR WASH CENTERS .......................................................................................................... 7 POLLUTANTS IN CAR WASH WASTEWATER: SOURCES AND THEIR IMPACT ON THE ENVIRONMENT .. 8 CURRENT PROCEDURE AVAILABLE TO DISCHARGE THE WASTEWATER FROM CAR WASH CENTERS12 WATER QUALITY CRITERIA FOR RECYCLING OF TREATED CAR WASH WASTEWATER .................... 13 DIFFERENT TREATMENT SYSTEMS TO RECYCLE THE CAR WASH WASTEWATER ............................. 14 CONVENTIONAL TREATMENT AND MEMBRANE BASED TREATMENT ............................................... 24 PROPOSED RESEARCH ..................................................................................................................... 30 Treatment system 1: Coagulation, flocculation, sedimentation, sand filtration,

ultrafiltration using ceramic membrane and reverse osmosis ............................................................ 30 Treatment system 2: Enhanced Membrane Bioreactor (eMBR) ........................................... 33 CONCLUSION ................................................................................................................................... 41

CHAPTER 3 .................................................................................................................................................... 42

3 RECYCLING OF CAR WASH WASTEWATER TREATED BY CERAMIC ULTRAFILTRATION AND REVERSE OSMOSIS MEMBRANES ................................................................................................. 42

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Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

INTRODUCTION ............................................................................................................................... 42 MATERIALS AND METHODS ............................................................................................................ 42 Sample collection and water quality analysis.......................................................................... 43 Experimental set-up for the treatment system 1 ...................................................................... 44 Coagulation-flocculation .......................................................................................................................... 44 Sand Filtration ........................................................................................................................................... 45 Ceramic Ultrafiltration Membrane ........................................................................................................ 45 Reverse Osmosis ........................................................................................................................................ 46 RESULTS AND DISCUSSION ............................................................................................................... 47 Raw car wash wastewater quality analysis .............................................................................. 48 Coagulation-flocculation .......................................................................................................... 49 Sand filtration ............................................................................................................................ 50 Ultrafiltration with ceramic membrane ................................................................................... 55 Reverse osmosis ......................................................................................................................... 58 Changes to water quality parameters along the treatment processes .................................... 59 Change in pH along the treatment process ............................................................................................ 59 Change in EC and TDS along the treatment process ........................................................................... 60 Change in turbidity and suspended solids along the treatment process ............................................ 62 Change in COD along the treatment process ........................................................................................ 63 Change in total phosphorus along the treatment process .................................................................... 63 Change in total nitrogen, ammonia, nitrate, and nitrite along the treatment process ..................... 64 Change in heavy metals (copper and zinc) along the treatment process ........................................... 66 Particle Size Distribution ......................................................................................................................... 67 Waste generation ........................................................................................................................ 68 Waste generation from coagulation .................................................................................................... 68 Backwash during sand filtration.......................................................................................................... 69 Retentate from ceramic ultrafiltration membrane .......................................................................... 69 Retentate from reverse osmosis ........................................................................................................... 69 Comparison of treated water with the criteria of recycling water and Standards ....................... 69 Justification for using ceramic ultrafiltration membrane and reverse osmosis .......................... 70 CONCLUSIONS ................................................................................................................................. 70

CHAPTER 4 .................................................................................................................................................... 72

RECYCLING THE CAR WASH WASTEWATER USING ENHANCED MEMBRANE

4 BIOREACTOR (EMBR) ................................................................................................................................ 72

INTRODUCTION ............................................................................................................................... 72 MATERIALS AND METHODS ............................................................................................................ 72 Experimental set-up of Enhanced membrane bioreactor ...................................................... 73 Influent chemical composition and sample collection ........................................................... 74 Analytical methods .................................................................................................................... 75 Experimental Plan .................................................................................................................... 76 Short term critical flux.............................................................................................................. 77 Determination the effect of hydraulic retention time (HRT) on permeate water quality ..... 78 Cleaning the membrane ............................................................................................................ 79 RESULTS AND DISCUSSION .............................................................................................................. 79 Car wash wastewater quality .................................................................................................... 79 Operational phases of the eMBR ............................................................................................. 81 Temporal variation of wastewater quality in eMBR ............................................................... 82 pH ................................................................................................................................................................ 82 Temperature .............................................................................................................................................. 83 Electrical Conductivity (EC) ................................................................................................................... 84 Total Dissolved Solids (TDS) ................................................................................................................... 85

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Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Relationship between electrical conductivity (EC) and total dissolved solids (TDS) ....................... 86 Dissolved Oxygen (DO) ............................................................................................................................ 87 Oxidation-Reduction Potential (ORP) ................................................................................................... 88 Relationship between dissolved oxygen (DO) and oxidation-reduction potential (ORP) ................ 90 Temporal variation of Flux and TMP ..................................................................................... 91 Temporal variation of turbidity of permeate ........................................................................... 92 Effect of Flux on Transmembrane Pressure (TMP) and the Turbidity of the permeate ..... 93 Changes to Mixed Liquor Suspended Solids (MLSS) in reactors with time ......................... 94 Removal of Organic Compounds ............................................................................................. 97 Nitrogen removal ....................................................................................................................... 98 Phosphorus removal ........................................................................................................... 101 Mass Balance on the eMBR System .................................................................................. 103 Common short term critical flux ........................................................................................ 104 Particle size analysis ........................................................................................................... 111 Effect of Hydraulic Retention time (HRT) on permeate water quality ........................... 112 Removal of E.coli by the eMBR ......................................................................................... 114 Removal of surfactants ....................................................................................................... 115 Removal of organic substances by the eMBR ................................................................... 115 Removal of Oil and Grease by eMBR ................................................................................ 115 SEM Analysis of Membrane .............................................................................................. 115 Comparison of permeate water quality with recycle water quality standards ................ 116 Comparison of permeate quality between two treatment systems .................................... 117 CONCLUSIONS .......................................................................................................................... 118

CHAPTER 5 .................................................................................................................................................. 120

5 CONCLUSIONS AND RECOMMENDATIONS ............................................................................... 120

CONCLUSIONS ............................................................................................................................... 120 RECOMMENDATIONS FOR FUTURE WORK ON EMBR SYSTEMS ..................................................... 122

APPENDIX ................................................................................................................................................... 128

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

LIST OF FIGURES

Figure 2-1 Main origins of pollutants in wastewater emanating from car wash .................................................... 9 Figure 2-2 Current procedures to discharge the wastewater from car wash centers ............................................ 13 Figure 2-3 A schematic diagram of first treatment system consisting of coagulation-flocculation, sand filtration, ceramic ultrafiltration membrane and reverse osmosis .............................................................................. 31 Figure 2-4 A schematic diagram of eMBR ........................................................................................................ 34 Figure 2-5 A schematic diagram of Biological Phosphorus removal .................................................................. 37 Figure 2-6 SEM picture of Hollow Fibre Membrane ........................................................................................ 38 Figure 3-1 A schematic diagram of treatment system 1 comprising coagulation, flocculation, sedimentation, sand filtration, ceramic ultrafiltration and reverse osmosis membrane ............................................................... 43 Figure 3-2 Experimental set-up of ceramic ultrafiltration membrane to filter pre-treated car wash wastewater .. 46 Figure 3-3 Experimental set up of reverse osmosis system to treat pre-treated car wash wastewater .................. 47 Figure 3-4 Turbidity of supernatant after jar test with different doses of FeCl3 as coagulant .............................. 49 Figure 3-5 Turbidity of supernatant after jar test with different doses of alum as coagulant ............................... 49 Figure 3-6 Removal of particles from car wash wastewater during sand filtration.............................................. 50 Figure 3-7 Grain size distribution curve of sand filter particles .......................................................................... 52 Figure 3-8 Area calculation by particles for surface area coverage .................................................................... 53 Figure 3-9 Specific surface area coverage by various particles during sand filtration ......................................... 55 Figure 3-10 Change in flux with time during ceramic membrane filtration ........................................................ 55 Figure 3-11 Change of permeate EC with time during ceramic ultrafiltration membrane treatment.................... 56 Figure 3-12 Change in permeate pH with time during ceramic ultrafiltration membrane treatment .................... 56 Figure 3-13 Change in permeate turbidity with time during ceramic ultrafiltration membrane treatment ........... 57 Figure 3-14 Relationship between flux and EC during ceramic ultrafiltration membrane treatment ................... 57 Figure 3-15 Change in flux with time during reverse osmosis experiment ......................................................... 58 Figure 3-16 Change in pH with time during reverse osmosis experiment ........................................................... 58 Figure 3-17 Change in EC with time during reverse osmosis experiment .......................................................... 59 Figure 3-18 Change in turbidity with time during reverse osmosis experiment .................................................. 59 Figure 3-19 Change in pH of the effluent emerging from each treatment process of the Treatment System 1 .... 60 Figure 3-20 Change in EC of the effluent emerging from each treatment process of the Treatment System 1 .... 60 Figure 3-21 Change in TDS of the effluent emerging from each treatment process of the Treatment System 1 .. 61 Figure 3-22 Relationship between EC and TDS of the effluents along the treatment processes .......................... 61 Figure 3-23 Change in turbidity of the effluent emerging from each treatment process of the Treatment System 1

................................................................................................................................................................. 62

Figure 3-24 Change in suspended solids of the effluent emerging from each treatment process of the Treatment

System 1 ................................................................................................................................................... 62

Figure 3-25 Change in the average concentration of COD in the effluent emerging from each treatment process

of the Treatment System 1 ........................................................................................................................ 63

Figure 3-26 Change in the average concentration of total phosphorus in the effluent emerging from each

treatment process of the Treatment System 1 ............................................................................................ 64

Figure 3-27 Change in the average concentration of ammonia in the effluent emerging from each treatment

process of the Treatment System 1............................................................................................................ 65 Figure 3-28 Change in the average concentration of nitrate in the effluent emerging from each treatment process of the Treatment System 1 ........................................................................................................................ 65

Figure 3-29 Change in the average concentration of nitrite in the effluent emerging from each treatment process

of the Treatment System 1 ........................................................................................................................ 65

Figure 3-30 Change in the average concentration of total nitrogen in the effluent emerging from each treatment

process of the Treatment System 1............................................................................................................ 66 Figure 3-31 Change in the average concentration of copper in the effluent emerging from each treatment process of the Treatment System 1 ........................................................................................................................ 66 x

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Figure 3-32 Change in the average concentration of zinc in the effluent emerging from each treatment process of the Treatment System 1 ............................................................................................................................ 67 Figure 4-1 Diagram of methodology ................................................................................................................. 72 Figure 4-2 A schematic diagram of the Enhanced Membrane Bioreactor (eMBR) ............................................. 74 Figure 4-3 Sampling point of the water quality parameter analysis in eMBR systems ....................................... 75 Figure 4-4 Schematic diagram of the critical flux determination by the flux-step method .................................. 78 Figure 4-5 Temporal variation of pH ................................................................................................................. 82 Figure 4-6 Change of pH in all reactors during the eMBR processes ................................................................ 83 Figure 4-7 Temporal variation of temperature ................................................................................................... 84 Figure 4-8 Temporal variation of electrical conductivity ........................................ Error! Bookmark not defined. Figure 4-9 Temporal variation of Total Dissolved solids ........................................ Error! Bookmark not defined. Figure 4-10 Relationship between TDS and EC along the eMBR processes ...................................................... 87 Figure 4-11 Temporal variation of dissolved oxygen ......................................................................................... 88 Figure 4-12 Temporal variation of ORP ............................................................................................................ 89 Figure 4-13 Relationship between dissolved oxygen and oxidation-reduction potential ..................................... 90 Figure 4-14 Temporal variation of flux through the membrane submerged in the AMBR .................................. 91 Figure 4-15 Temporal variation of TMP through the membrane submerged in the AMBR ................................ 92 Figure 4-16 Temporal variation of turbidity of the permeate ............................................................................. 93 Figure 4-17 Change of TMP with flux .............................................................................................................. 94 Figure 4-18 Change of permeate turbidity with flux .......................................................................................... 94 Figure 4-19 Temporal variation of MLSS in Anaerobic, Anoxic and AMBR tank ............................................. 95 Figure 4-20 Average COD: TN:TP in the mixed liquor of the feed tank ............................................................ 96 Figure 4-21 Average COD: TN:TP in the mixed liquor of the anaerobic tank .................................................... 96 Figure 4-22 Average COD: TN:TP in the mixed liquor of the anoxic tank ........................................................ 97 Figure 4-23 Average COD: TN:TP in the mixed liquor of the AMBR tank ....................................................... 97 Figure 4-24 Temporal variation of COD in all reactors as well as removal efficiencies ..................................... 98 Figure 4-25 Temporal variation of TN in all reactors as well as removal efficiencies ........................................ 99 Figure 4-26 Temporal variations of NH3-N in all reactors as well as the removal efficiencies.......................... 100 Figure 4-27 Temporal variations of NO2-N in all reactors ............................................................................... 100 Figure 4-28 Temporal variations of NO3-N in all reactors ............................................................................... 100 Figure 4-29 Temporal variation of TP in all reactors ....................................................................................... 102 Figure 4-30 A schematic diagram for mass balance in the eMBR system ........................................................ 103 Figure 4-31 The change of TMP with time (Continuous mode) ....................................................................... 106 Figure 4-32 The change of TMP with time (Intermittent mode) ....................................................................... 106 Figure 4-33 Temporal variation of Flux (Continuous mode) ............................................................................ 107 Figure 4-34 Temporal variation of Flux (Intermittent mode) ........................................................................... 107 Figure 4-35 Change in the permeate turbidity with membrane flux (continuous mode) .................................... 110 Figure 4-36 Change in the permeate turbidity with membrane flux (intermittent mode)................................... 110 Figure 4-37 Relationship between critical flux and MLSS ............................................................................... 111 Figure 4-38 Effect of HRT on permeate turbidity ............................................................................................ 113 Figure 4-39 Effect of HRT on COD Removal percentage ................................................................................ 113 Figure 4-40 Effect of HRT on permeate flux and TMP of membrane .............................................................. 114 Figure 4-41 SEM of new membrane (MF)....................................................................................................... 116 Figure 4-42 SEM of used membrane in MBR.................................................................................................. 116 Figure 5-1 A schematic diagram of treatment system 1 ................................................................................... 120 Figure 5-2 A schematic diagram of treatment system 2 .................................................................................. 121

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

LIST OF TABLES

Table 1-1 Different types of Car washing methods and their ratings based on consumption of potable water ....... 4 Table 2-1 Types of pollutants in car wash wastewater and their sources and environmental impacts ................... 9 Table 2-2 Surfactants found in different car wash wastewater and the treatment methods used to remove the

surfactants ................................................................................................................................................ 10

Table 2-3 Oil and grease found in different car wash wastewater and the treatment methods used to remove the

oil and grease ........................................................................................................................................... 11 Table 2-4 Different types of organics present in the car wash wastewater .......................................................... 11 Table 2-5 Recycling water quality criteria for car wash ..................................................................................... 14 Table 2-6 Different types of treatment systems used to treat car wash wastewater ............................................. 14 Table 2-7 General characteristics of membrane processes ................................................................................. 18 Table 2-8 Different treatment methods used in car wash wastewater treatment .................................................. 22 Table 2-9 Car wash wastewater treatment systems based on conventional treatment ......................................... 25 Table 2-10 Car wash wastewater treatment methods based on membrane .......................................................... 28 Table 2-11 Summary of the economic evaluation of car wash wastewater treatment ......................................... 29 Table 2-12 The ratio of COD:TN:TP in different wastewater treated by MBR .................................................. 36 Table 2-13 Membrane Characteristics ............................................................................................................... 38 Table 3-1 Characteristics of coagulants used in this study ................................................................................. 44 Table 3-2 Grain size analysis of the sand used in filtration ............................................................................... 45 Table 3-3 Properties of reverse osmosis membrane ........................................................................................... 47 Table 3-4 Car wash wastewater quality collected at different times .................................................................. 48 Table 3-5 Surface area coverage by different particles during sand filtration .................................................... 54 Table 3-6 Changes of particle after treatment ................................................................................................... 67 Table 3-7 Comparison of treated water quality with standards ........................................................................... 70 Table 4-1 Components of the synthetic wastewater and their concentrations ..................................................... 75 Table 4-2 Raw car wash wastewater quality ...................................................................................................... 80 Table 4-3 Operating phases of eMBR................................................................................................................ 81 Table 4-4 Average value of pH along the eMBR processes ............................................................................... 83 Table 4-5 Average value of temperature along the eMBR processes .................................................................. 84 Table 4-6 Average value of EC (μS/cm) along the eMBR processes .................................................................. 85 Table 4-7 Average value of Total Dissolved Solids along the eMBR processes ................................................. 86 Table 4-8 The average value of TDS and EC for different phases along the eMBR processes ............................ 87 Table 4-9 Average value of dissolved oxygen along the eMBR processes ......................................................... 88 Table 4-10 Average value of ORP (mV) along the eMBR processes ................................................................. 89 Table 4-11 The average value of DO and ORP of different phases in eMBR system ......................................... 90 Table 4-12 Average value of Flux and TMP along the eMBR processes ............................................................ 92 Table 4-13 Average value of COD (mg/L) along the eMBR processes .............................................................. 98 Table 4-14 The value of TN, NH3-N, NO2-N, NO3-N along the eMBR processes ............................................ 101 Table 4-15 Average value of total phosphorus (mg/L) along the eMBR processes ........................................... 102 Table 4-16 Mass balance on the eMBR system for 100% car wash wastewater (HRT 206 hr) ......................... 104 Table 4-17 Summary of the critical flux tests (continuous mode) .................................................................... 105 Table 4-18 Summary of the critical flux tests (intermittent mode) ................................................................... 105 Table 4-19 Average flux, average TMP, rate of fouling with corresponding flux during critical flux test

(continuous mode) .................................................................................................................................. 109

Table 4-20 Average flux, average TMP, rate of fouling with corresponding flux during critical flux test

(intermittent mode) ................................................................................................................................. 109 Table 4-21 Effect of HRT on permeate quality and membrane flux and TMP.................................................. 112 Table 4-22 Relationship between Flux, TMP with HRT along the eMBR processes ........................................ 114

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Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Table 4-23 Comparison of the quality of the effluent from eMBR with the water quality standards required for

recycling................................................................................................................................................. 117 Table 4-24 Comparison of permeate quality between two treatment systems ................................................... 118

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Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

LIST OF ABBREVIATIONS

COD TN TP C:N:P DO EC TDS ORP EPA F/M FTIR SEM EDX HRT SRT MBR eMBR MF UF NF RO MLSS TMP AR1 AR2 AMBR UV A2O PAH PCBs GC-MS MBAS LAS ABS MTBE TH CFU Chemical Oxygen Demand Total Nitrogen Total Phosphorus Carbon to Nitrogen and Nitrogen to Phosphorus ratio Dissolved Oxygen Electrical Conductivity Total Dissolved Solids Oxidation Reduction Potential Environment Protection Authority Food to Microorganism Fourier Transform Infra-Red Scanning Electron Microscopy Energy-dispersive X-ray Hydraulic Retention Time Solids Retention Time Membrane Bioreactor Enhanced Membrane Bioreactor Microfiltration Ultrafiltration Nanofiltration Reverse Osmosis Mixed Liquor Suspended Solids Transmembrane pressure Anaerobic Bioreactor Anoxic Bioreactor Aerobic Membrane Bioreactor Ultraviolet Anaerobic, Anoxic and Oxic Polycyclic Aromatic Hydrocarbons Polychlorinated Biphenyls Gas Chromatograph with Mass Selective Detector Methylene blue active substances Linear Alkylbenzene Sulphonates Alkylbenzene Surfactant Methyl Tert-Butyl Ether Total Hydrocarbon Colony forming unit

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Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

COPYRIGHT STATEMENT

This thesis may be freely copied and distributed for research and study; however, no part of this thesis or the information contained therein may be included in or referred to in publication without proper reference and acknowledgment.

(Shamima Moazzem) 08 June 2017 © Shamima Moazzem

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Chapter 1

1 Introduction

Background

Car is a convenient and accessible way of transport for our daily life and its demand is

increasing every day. According to the Motor Vehicle Census (MVC) in 2016, there are 18.4

million registered motor vehicles in Australia (Australian Bureau of Statistics, 2016). Demand

for car washing centers is increasing for better maintenance of these cars. An average of 50 to

100 gallons (189 to 378.5 litres) of fresh water is required for a single professional car wash

(Al-Odwani et al., 2007). On the other hand, a significant amount of wastewater is produced

every day due to washing of cars. An extensive research has determined that over 35 billion

litres of contaminated wastewater are being disposed of rather than recycled from 10,000 car

wash centers in Australia each year (Boluarte et al., 2016).Wastewater from car wash contains

different types of pollutants which is a threat to the environment if this ends up in soil and water

without treatment. These wastewater contains petroleum hydrocarbon waste (diesel and motor

oil), heavy metals such as copper, lead and zinc, nutrients (phosphorus and nitrogen),

surfactants, suspended solids, microorganisms, sand and dust (Boluarte et al., 2016, Zaneti et

al., 2011, Etchepare et al., 2014, Australian Car Wash Association, n.d). Moreover, car oil is

highly toxic such that just one litre of oil can contaminate one million litres of water (Australian

Car Wash Association, n.d). When soaps and other solvents are used to clean cars, they dissolve

not only dirt and grease into the wastewater but also toxic surfactants, hydrocarbons and heavy

metals such as copper, lead, and zinc. This cocktail of waste far exceeds the accepted health

standards and destroys environments by receiving car wash wastewater. Different researchers

have identified the effects of untreated disposal of car wash wastewater in such environments.

Therefore, further research is essential to minimize the wastage of water and reduce the

environmental impact on rivers, creeks, lakes, and coastlines. Appropriate treatment processes

applied to treat car wash wastewater enable us to reuse the treated water at car wash facilities

and effectively isolate pollutants from the wastewater.

Description of the Proposed Research

Different technologies have been used to evaluate the treatment of car wash wastewater from

last few years, and those treatment technologies can be divided as conventional treatment

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

technologies and membrane based technologies. After critically evaluating the literature review

it is found that membrane based technologies can produce high quality treated water compared

to conventional treatment. Numerous researchers have used different membranes to treat the

car wash wastewater in combination with coagulation, flocculation, and sedimentation. The

waste generated from those treatment processes is an issue. This research aimed to develop a

treatment method using membrane based technology which will be able to produce higher

quality effluent, generating minimal waste with a small footprint for recycling wastewater from

the car wash.

Two different membrane based technologies were selected in this research.

A. Treatment system 1-This treatment system was a combination of coagulation-

flocculation, sand filtration, ceramic ultrafiltration membrane and reverse osmosis

B. Treatment system 2 -An enhanced membrane bioreactor (eMBR)

An enhanced membrane bioreactor (eMBR) comprised of an anaerobic bioreactor (AR1), an

anoxic bioreactor (AR2), an aerobic membrane bioreactor (AMBR) and a UV disinfection unit.

Aim and Objective

The main aim of this research is to develop a viable solution to treat and reuse car wash

wastewater. To do so, two treatment systems were evaluated. The first treatment system

comprised of coagulation-flocculation and ceramic ultrafiltration membrane and reverse

osmosis and the second treatment system is enhanced membrane bioreactor (eMBR). The

following objectives were achieved by using these two systems:

From treatment system 1:

• Evaluating the performance of coagulation-flocculation, sand filtration with membrane

systems;

• Monitoring and assessing the treated water quality.

From treatment system 2:

• Evaluating the performance of eMBR;

• Optimising residence time of eMBR;

• Monitoring the critical flux of membrane;

• Monitoring and assessing the treated water quality.

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Research Questions

The following research questions were answered to fulfil the aims of this research:

• How effective is it to use coagulation-flocculation, sand filtration, and membrane

systems to recycle the car wash wastewater?

•

Is it feasible (in terms of quality) to use eMBR process to recycle the car wash

wastewater?

• What are the relationships among operating parameters (for example, How the

transmembrane pressure is affected with time during different hydraulic retention time

in Aerobic Membrane Bioreactor (AMBR)? What is the critical flux during the

operation in AMBR?)

Scope of the Research

The scope of this research covers the following:

• Analyse the water quality parameters after coagulation-flocculation, sand filtration, and

membrane systems

• To analyse the water quality parameters at different locations of the eMBR system such

as feed, effluents from AR1, AR2, and AMBR and the Permeate

• Monitor the changes to the transmembrane pressure and permeate flux with time at

different hydraulic retention time for evaluating the performance of the membrane

• Comparative study between coagulation-flocculation, sand filtration with membrane

systems and eMBR with respect to treated water quality

Expected Deliverables

The outcomes of this research are to develop a viable solution and provide concrete guideline

to:

• Provide a sustainable treatment of car wash wastewater and recycle the water to reduce

the large amount of water demand for car washing;

• Evaluating the performance of eMBR for an extended period.

Rationale of the Research

The following sub-sections explained the main motivations of this research.

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Importance of undertaking this research

The consumption of water during car wash is a main concern in the world as recycling of water

is a major issue around the globe. Individual private cleaning of car has the risk of ecological

effect on the environment as the water run off to the drainage system. Therefore, many countries

regulate for using car wash center to wash the cars (Janik and Kupiec, 2007). On the other hand,

it is required to find out a treatment method for recycling wastewater from car wash centers

which can produce high-quality recycled water with small footprint and the system is easy to

maintain. From these points of view, membrane based treatment system consists of ceramic

ultrafiltration membrane with reverse osmosis and eMBR were selected to treat and recycle the

car wash wastewater.

Benefit of this research to the Community

To address the wastage of water by car wash, the Australian Car Wash Association introduced

five-star rating scheme which depends on the amount of potable water used by equipment in a

standard wash and rates the water efficiency of that equipment. Table 1.1 shows the amount of

potable water required for different types of car washing and their rating.

Table 1-1 Different types of Car washing methods and their ratings based on consumption of potable water

Average potable water consumption per car wash Method of washing Star Rating (According to the Australian Car Wash Association) (Source: Savewater) (Source: Lenntech)

400 litres Not rated

150 litres Not rated

10-50 litres 5 Washing cars by hand with a hose Conventional car wash installation Car wash installation with water recycling system

[Rating Criteria: Not Rated = Over 140; Star Rating 3 = 121-140; Rating 4 = 101-120; Rating 5 = less

than 100 litres per wash (Savewater, n.d.)] [Consumption of water per car wash, Source: Lenntech

From Table 1.1 it is evident that if car wash centers use water recycling system, then it can save

at least 100 litres per wash which will be benefitted for the community. Contaminants from the

wastewater will not be a threat to the environment if regulated cleaning processes are followed.

(Lenntech, n.d.) (n.d means no date as the date of creation of the webpage is not available)]

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Significance of this Project

A viable system was developed for the treatment of car wash wastewater which can be easily

constructed at a car wash facility to recycle the treated wastewater. An enhanced membrane

bioreactor (eMBR) was selected for this project considering the satisfactory results of MBR

used in a project at Deakin University for recycling the car wash wastewater (Boluarte et al.,

2016). But in that project, MBR was run only for three months and the performance of the

membrane; critical flux and the effect of hydraulic retention time on water quality were not

evaluated. Moreover, a further detailed study was necessary for the commercial type application

of this system for recycling the car wash wastewater. In this research, the performance of the

eMBR was evaluated in detail. However, first treatment system (coagulation-flocculation, sand

filtration, ceramic ultrafiltration membrane and reverse osmosis) was selected to compare the

permeate water quality between the two systems.

Thesis outline

This thesis consists of 5 chapters. The details of each chapter are described below.

Chapter 1: Introduction

This chapter provides an overall summary of this research with research scope, objective and

rational. The thesis outline is also described here.

Chapter 2: Literature review

This chapter mainly includes the literature review that was carried out during this research. In

the first stage, different types of car wash centers and pollutants generated with current disposal

systems are explained briefly. Different wastewater treatment technologies used by different

researchers to recycle the car wash wastewater are discussed in the second stage. The third stage

explained the basis on the selection of membrane based technology with two different

membrane based treatment systems.

Chapter 3: Recycling of car wash wastewater treated by Ceramic Ultrafiltration and

Reverse Osmosis Membranes

This chapter describes the details of the experimental plan of first treatment system which

consists of coagulation-flocculation, sand filtration, ceramic ultrafiltration membrane and

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

reverse osmosis. The details of methodology with analysis of water quality changes after each

step are also included here.

Chapter 4: Recycling the car wash wastewater using Enhanced Membrane Bioreactor

(eMBR)

The details of experimental set-up of eMBR with material and methods, data analysis, short

term critical flux (intermittent and continuous mode), the role of microorganisms, relationship

between hydraulic retention time with permeate qualities are described here. A comparative

study based on the effluent quality of two different systems (Treatment system 1 and Treatment

system 2) to treat the car wash wastewater for recycling purpose is discussed as well.

Chapter 5: Conclusions and Recommendations

The overall conclusions and future scope of this research are described in this chapter.

Conclusions

Evaluating the performance of first treatment system and eMBR for recycling the car wash

wastewater is the main concern of this research. To fulfil this objective eMBR was run for an

extended time. The permeate quality and the performance of eMBR for recycling the car wash

wastewater were investigated. A comparison study between two treatment systems were carried

out, and the findings are described in detail in this thesis.

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Chapter 2

2 Literature Review

Introduction

The number of the vehicles is increasing day by day for maintaining the comfort of our daily

life. The statistics show that this number has grown dramatically over the last 10 years in

Australia. Since 2006, the increasing rate is 27.8%, when there were 14.4 million registered

vehicles (Australian Bureau of Statistics, 2006). It is projected by Australia New Car Sales

organization that around 101,000 new cars will be sold by 2020 (Trading Economics Australian

New Car Sales, 2017). This increased number of cars also needs to be maintained properly

either by washing these cars at home or in car wash centers. Many countries such as

Switzerland, Germany, Netherlands are imposing the rules to stop washing car at home due to

ecological issues as wastewater from car wash ultimately goes to the stormwater system (Janik

and Kupiec, 2007). Therefore, to minimize the effect on the stormwater systems, the numbers

of car wash centers are being increased. With the increased number of car wash centers, the

consumption of water for washing cars and the disposal of generated wastewater become

another major issue. Recycling of treated car wash wastewater will be the best option to reduce

the water consumption. Different technologies have been used to evaluate the treatment of car

wash wastewater in the last few years (Li et al., 2007, Hamada and Miyazaki, 2004, Zaneti et

al., 2011). The first section of this chapter discusses the types of car wash centers and their

water requirements. The sources of pollutants in car wash wastewater and its environmental

impact and current disposal methods used by car wash centers also discussed in this section. In

the second section, different treatment technologies used by researchers such as coagulation-

flocculation, sand filtration, oxidation, membrane filtration, etc. in treating the car wash

wastewater along with the quality of treated car wash wastewater (hereafter called effluent) are

discussed in detail. The reason for selecting membrane based technology for this research and

the details of ceramic ultrafiltration membrane with reverse osmosis and enhanced membrane

bioreactor (eMBR) are described in the last section of this chapter.

Types of car wash centers

Commercial car wash centers can be divided into different types such as self- serve, in-bay

automatic, conveyor, touch free and hybrid car washing based on the construction and washing

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

technologies. In addition, the consumption of water varies in every system. For example, self-

service, in bay automatic, conveyor (friction) and conveyor (frictionless) require 15, 50-60 and

65.8 and 85.3 gallons of fresh water per vehicle washing respectively (Brown C, 2000).

Queensland state in Australia and some other countries in Europe have restricted the use of

fresh water for a single car wash to less than 70 L (Zaneti et al., 2011). In Belgium, the water

consumption rate is very high (up to 400 L per wash) in the automatic car wash bays (Boussu

et al., 2007, Zaneti et al., 2011). Furthermore, some car wash centers use rain water to save

potable water for the initial car wash by establishing a rain water system in the car wash centers

(Zaneti et al., 2011). Lenntech has published the required amount of water for different car

washing services and showed that car wash installation with recycling system requires only 10-

50 L of water in contrast to the conventional car wash installation system which requires 150

L (Lenntech, n.d.). Therefore, based on this information it can be said that car wash centers

with recycling systems can save a huge amount of water and therefore establish recycling

systems is the best way to reduce the water consumption in car wash centers.

Pollutants in car wash wastewater: Sources and their impact on the environment

Car wash centers produce large amounts of wastewater every year which ends up in the

sewerage system. In Australia, more than 35 billion litres of contaminated wastewater are

produced from 10,000 car wash centers every year (Boluarte et al., 2016). Mohamed et al.

(2014) reported that 15 million litres of polluted water could enter into the storm water system

annually by washing cars in New South Wales (NSW). These car wash wastewaters contain

different types of impurities such as organic and inorganic substances, microorganisms, heavy

metals and their sources also vary. Some pollutants originate from the traffic, and the others

originate from the chemicals used during the car wash. Detail of sources of the impurities are

illustrated in Figure 2.1 (Boluarte, 2014, Janik and Kupiec, 2007).

According to the International Car Wash Association, the primary constituents of concern to

professional car wash operators are total suspended solids (TSS), total dissolved solids (TDS),

oil and grease, biochemical oxygen demand (BOD), chemical oxygen demand (COD),

detergent, heavy metals such as lead, zinc and trace amounts of other priority metals (Brown

C, 2000). Moreover, the Australian Car Wash Association (ACWA) has provided the quantities

of individual contaminants found in the runoff from washing cars as illustrated in Table 2.1

(Boluarte, 2014, Australian Car Wash Association, n.d).

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Figure 2-1 Main origins of pollutants in wastewater emanating from car wash

(Janik and Kupiec, 2007, Boluarte, 2014)

Table 2-1 Types of pollutants in car wash wastewater and their sources and environmental impacts

(Australian Car Wash Association, n.d, Boluarte, 2014)

Parameters

Type of Pollution

Sources of pollutants

Impact on the environment

Average concentration of Car wash waste water

Suspended Solids

200 mg/L

• Destroy marine environment

Inorganic pollutants

• Exceed the

80 NTU

Turbidity

• Traffic, road surfacing, atmospheric pollutants

0.3 mg/L

Dissolved Copper

accepted health standards

Heavy Metals

• Brake linings, rubber, rust

0.02 mg/L

Lead

• Eutrophication

• Car wash

Zinc

0.5 mg/L

Total Organic Carbon

59 mg/L

chemicals such as detergents

27 mg/L

Surfactants

Organic Pollutants

• Tiny exhaust particles

5 mg/L

Hydrocarbon

Over the past few years, research has been conducted by various research groups to treat car

wash wastewater using different treatment methods (Bhatti, 2011, Mohamed et al., 2014, Li et

al., 2007). Most of the researchers had considered chemical oxygen demand (COD), total

nitrogen (TN), total phosphorus (TP), suspended solids and turbidity, but many of them had

not mentioned about detergents, oil and grease and organic pollutants in their research. But

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

these pollutants have major impacts on the environment. In the following paragraphs, the

different impurities especially the detergents, oil and grease and organic pollutants found in car

wash wastewater are described.

Detergents: Detergents which are used as cleaning agents in car wash centers contain different

types of surfactants. These surfactants can be classified as anionic, cationic and non-ionic (Tu

et al., 2009). These surfactants are environmentally persistent and bio-accumulative and can be

a cause for health and environmental problems. Table 2.2 provides details of the surfactants

present in car wash wastewater and the treatment methods used to remove them from the water.

Table 2-2 Surfactants found in different car wash wastewater and the treatment methods used to remove the surfactants

Treatment applied References Surfactants Removal efficiency

40%

Flocculation column

Zaneti et al.

Methylene blue

flotation, sand

(2011)

active

filtration, chlorination

substances

(MBAS)

(anionic)

Alkylbenzene

3-20 mg/L

<0.05 mg/L

98 -99.7% Sedimentation,

al.

surface degreasing,

(2009)

surfactant

sand filtration,

(ABS) (anionic)

ozonation, UV

irradiation,

membrane separation

Linear

0.014 μg/L-

Not available

Not

Not available

Sablayrolles et

alkylbenzene

20.12 mg/L

available

al. (2010)

sulphonates

(LAS) (anionic)

Initial concentration (in car wash wastewater) 21 mg/L Final concentration (after treatment) 12 mg/L

Oil and Grease: Oil can be present in the water in different forms such as free (>150) (μm),

dispersed (50-150) (μm), emulsified (0.1-50) (μm) and soluble (<0.1) (μm). The oil and grease

found in car wash wastewater and the treatment methods used by different researchers are

shown in Table 2.3.

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Table 2-3 Oil and grease found in different car wash wastewater and the treatment methods used to remove the oil and grease

Oil/Grease Applied treatment References Removal efficiency

Initial concentration (in carwash wastewater) 22 mg/L Final concentration (after treatment) 12 mg/L Oil 45% Flocculation column Zaneti et al.

flotation, sand (2011)

filtration, chlorination

Fossil oil 500-3000 4-20 mg/L 99.2- Sedimentation, surface Tu et al.

and grease mg/L 99.3% degreasing, sand (2009)

filtration, ozonation,

UV irradiation,

membrane separation

Organics: Different types of organics can be present in the car wash wastewater. Sablayrolles

et al. (2010) investigated three different car wash wastewaters and stated that the concentration

of polycyclic aromatic hydrocarbon (PAH), polychlorinated biphenyls (PCB), methyl tert-

butyl ether (MTBE) and total hydrocarbon presented in car wash wastewater have a tremendous

impact on stormwater quality. Table 2.4 illustrated the concentration of these impurities in

wastewater, and these should be removed or reduced before being discharged into the sewer.

Table 2-4 Different types of organics present in the car wash wastewater

(Sablayrolles et al., 2010)

Organic pollutant Type of carwash centers Concentration

Polycyclic aromatic hydrocarbon (PAH) (μg/L) Truck car wash 1.778

Self-service car wash 0.372

Petrol station car wash 0.319

Polychlorinated biphenyls (PCB) (μg/L) Truck car wash 1.16

Self-service car wash 0.41

Petrol station car wash 0.19

Methyl tert-butyl ether (MTBE) (μg/L) Truck car wash 2.4

Self-service car wash 0.3

Petrol station car wash 0.3

Total hydrocarbon (TH) (mg/L) Truck car wash 0.56

Self-service car wash 0.02

Petrol station car wash 0.09

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Impacts of the car wash wastewater pollutants

Various studies have been conducted on analysing the impact of the car wash wastewater

(Mohamed et al., 2014, Hamada and Miyazaki, 2004). Research reveals that this wastewater

can deteriorate natural water quality as many of the premises discharge their wastewater

directly into the main drain (Mohamed et al., 2014). Moreover, its disposal into the sewerage

system without treatment can cause serious environmental problems. For example, some

detergents containing phosphate used for washing cars can cause excess algae to grow in local

waterways such as in the open drains or in other waterways (Mohamed et al., 2014). Moreover,

these car wash wastewater contains high concentrations of surfactants, oils, greases, waxes

which are toxic to aquatic life (Zaneti et al., 2012).

Current procedure available to discharge the wastewater from car wash centers

Eliminating or minimising the waste from the car wash center is essential to reduce the risk of

environmental pollution. Environmental Protection Authority (EPA-Victoria) has published a

flow chart on vehicle cleaning procedure and the disposal of waste from car wash center as

shown in Figure 2.2 (Victoria EPA, 2009). The flow chart clearly describes that the waste

should be removed from the water prior to discharge into the sewer and transported by a

licensed transporter for further treatment. This will incur significant cost to the owner of a car

wash center and recycling of treated car wash wastewater will be the best option to overcome

this problem.

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Figure 2-2 Current procedures to discharge the wastewater from car wash centers

(Victoria EPA, 2009)

Water quality criteria for recycling of treated car wash wastewater

Reclaimed (reuse, recycling) water is expressed as a ‘fit for purpose’ water where the

wastewater is treated by different treatment processes to meet the required criteria for a

particular use (Zaneti et al., 2011, Metcalf & Eddy, 2006). The criteria of recycling water for

vehicle washing must include public acceptance, aesthetic quality (odourless and low turbidity),

microbiological risk (low health risk) and chemical issues (Zaneti et al., 2012). Some countries

such as China and Belgium have set standards for recycling water for use in car washing. In

Australia, it is mentioned that the recycled water quality should meet class-A standards for

washing vehicles. The criteria for recycling water quality for vehicle washing are shown in

Table 2.5.

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Table 2-5 Recycling water quality criteria for car wash

Quality parameter Standards in Belgium (Boussu et al., 2007)

Recycled water Class A according to EPA Victoria 10 BOD (mg/L) < 25 (BOD5) Standards in China (Tiina Mononen (Ed.), 2013) 10 (BOD5)

COD (mg/L) < 125 50 (CODCr)

SS (mg/L) 5 < 60 5

Turbidity (NTU) < 2 - 5

pH 6-9 6.5–9 6.5–9

Oil (mg/L) 30

Suspended solids <3 (mg/L)

E. coli (org/100 mL) < 10

Different treatment systems to recycle the car wash wastewater

Numerous wastewater treatment technologies have been employed in the remediation of

pollutants present in car wash wastewater. These technologies may differ according to the car

wash service installation and its purpose, but the basic methods are same, such as separation

for taking the grit, oil, and grease out of wastewater, oxidation to remove odour and colour,

filtration to separate suspended solids and membrane filtration or de-ionization to remove high

total dissolved solids (Brown C, 2000). These treatment technologies can be divided into

physical and chemical type as shown in Table 2.6.

Table 2-6 Different types of treatment systems used to treat car wash wastewater

Physical treatment Chemical treatment

Coagulation Screening

Oxidation Sedimentation

Flotation

Filtration

Membrane treatment

A brief description of each treatment method is given in the following sub sections.

Adsorption

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Screening: A screen is a device with uniform size openings used to retain coarse materials

found in the influent wastewater which can damage subsequent process equipment. By

screening the effectiveness of the treatment process is also increased. Different researchers

used screening as a preliminary treatment to remove heavy particles from car wash wastewater.

Al-Odwani et al. (2007) used an inclined screen which was fixed in the settling tank to remove

sand, dirt, and grit from wastewater. Moreover, an oil skimmer was used to remove the oil, but

it could not remove the oil entirely.

Oil/ water separator: Oil/water separator used gravity force to separate oil from water. The

difference in densities between oil and water enables oil to float on top of the water and it can

be removed easily. Al-Odwani et al. (2007) used this oil/water separator to remove the

remaining oil from car wash wastewater when a skimmer was unable to remove it (Al-Odwani

et al., 2007). Another research group, Fall et al. (2007) found that the conventional oil/water

separator needs to be modified by adding a degreaser to break emulsified oil so that it could

meet the sewer discharging standards.

Sedimentation: Sedimentation is used to remove readily settleable solids by reducing the

suspended solids. Tu et al. (2009) used sedimentation and surface degreasing as preliminary

steps to remove large size solid wastes, suspended and solid greases present in car wash

wastewater.

Coagulation and flocculation: In the coagulation process, coagulants have been added

through rapid mixing to destabilize the particles by blending the chemicals with wastewater.

Flocculation is a transport step where the collisions between the destabilize particles are created

through slow mixing to form larger flocs that can be removed readily by settling or filtration

(Metcalf & Eddy, 2003). Zaneti et al. (2011) used Tanfloc SL coagulant/flocculant in their

flocculation column flotation system where the main mechanism was charge neutralization,

polymer bridging, and sweep flocculation.

Researchers have been using different types of coagulants such as natural and commercial

coagulants (Mohamed et al., 2014, Boluarte et al., 2016). A study by Mohamed et al. (2014)

demonstrated that natural coagulants have higher efficiency than commercial coagulants in

reducing the turbidity but not the COD from car wash wastewater. They illustrated that a natural

coagulant Moringa Oleifera could remove only 60% COD, but 90% turbidity, however

commercial coagulant (Alum) could remove 74% COD and 87% turbidity. Another research

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

by Bhatti (2011) used 80 mg/L alum (Al2(SO4)3.14H2O) in the mixing chamber, and they could

remove 92.35% COD.

Flotation: Flotation is a unit operation used to separate solid or liquid particles by introducing

fine gas (usually air) bubbles into the liquid phase. These bubbles attach to the particulate

matter, and the buoyant force of the combined particle and gas bubbles is great enough to cause

the particles to rise to the surface (Metcalf & Eddy, 2003). The main advantage of flotation

compared to sedimentation is to remove completely small or light particles within a short time.

After the flotation, the particles are collected by skimming. The application of column flotation

is used in different wastewater treatment such as for the treatment of oil and grease (removal

from water), metallic ions, and suspended solids (Zaneti et al., 2011). Bhatti (2011) applied

aeration for one hour to remove excess oil in car wash wastewater treatment, but scum was

needed to remove manually with a scraper after aeration.

Filtration: Filtration is used to remove the suspended solids and particulate material suspended

in a liquid by passing the influent through a filter bed comprised of a granular or compressible

filter medium. During its passage, the particulate impurities are brought into contact with the

surface of sand grains and held in position there. Those that consist of inert material are retained

until eventually removed during the cleaning process, while those capable of chemical or

biological degradation are converted into simpler forms that are either carried away in solution

or remain, with the inert material, for subsequent removal (Huisman and Wood, 1974).

Sand filtration is used as a pre-treatment step for membrane filtration. Tu et al. (2009) reported

the efficiency of the removal of suspended solids from car wash wastewater by sand filtration

and found that the removal efficiency is increased from 90% to 96% with the decrease in the

sand particle size (from 0.6-0.85 mm to 0.425-0.6 mm) but at the same time the production rate

of water decreased from 45 L/h to 30 L/h. They mentioned that the sand size in the range of

0.425-0.6 mm provides a better production rate of water with better removal efficiency.

Oxidation: Oxidation is used in car wash wastewater treatment to change the chemical

composition of certain compounds. Potassium permanganate can be used to oxidize the organic

pollutants which are a reason for causing odour and taste. But after oxidation, the precipitant

from oxidant needs to be removed which requires additional treatment (Abdelmoez et al., 2013).

Bhatti (2011) used hydrogen peroxide (H2O2) to oxidise most of the COD in the last chamber

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

of their treatment system, and it reduced a total of 94.4% COD after the treatment composed

of aeration, alum coagulation, and hydrogen peroxide oxidation.

Ozonation as oxidation: Ozone has considered as an effective oxidizing agent used widely in

the chemical water treatment process to decompose the dissolved compounds (Tu et al., 2009).

In this process, reactive oxygen species is produced which can react with organic compounds

and microorganisms. Ozonation can be used in various steps in the wastewater treatment

depending on the requirements. It is used as an efficient application by different researchers

for disinfection as well as for removing odour and colour causing compounds as it can degrade

the organic and inorganic pollutants. Tu et al. (2009) found that ozonation with UV irradiation

is very effective in removing surfactants, organic compound, and colour from car wash

wastewater but the combined process can only remove 40% fossil oil and grease. The main

drawbacks of ozonation are high cost and the short life span of ozone.

Membrane Filtration: Membrane filtration is a separation process to separate the particulate

and colloidal matter from a liquid including dissolved constituents (typically 0.0001 to 1.0 μm).

This technology is used to remove pollutants from car wash wastewater with high efficiency.

Basic Classification of Membranes:

Membrane process can be classified in different ways including (1) the type of material from

which the membrane is made, (2) the nature of the driving force, (3) the separation mechanism

and (4) the nominal size of the separation achieved. In the following paragraph, membrane

classification based on the material and different types of membrane process are described.

Membrane can be divided into two groups based on the material used for making it such as

organic polymer membranes (such as polythersulfone (PES), polyacrylonitrile (PAN),

polyvinylidene fluoride (PVDF), etc.) and inorganic membranes (such as ceramics, aluminium,

high-grade steel, glass and fibre reinformed carbon). Moreover, different types of membrane

process such as microfiltration, ultrafiltration, and nanofiltration are available which are used

to recycle the wastewater in car wash industry. General characteristics of those membrane

processes are shown in Table 2.7 with their operating pressure, pore size and the contaminants

removed.

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Table 2-7 General characteristics of membrane processes

(Metcalf & Eddy, 2003)

Filtration Type Operating Contaminants

Pressure (kPa) Removed Typical operating range (μm)

Microfiltration (MF) 7-100 0.08-2 protozoa and Bacteria, suspended solids

0.005-0.2 Ultrafiltration (UF) Bacteria, protozoa, suspended solids, biodegradable organics

70-700 (1-5 bar for cross-flow and 0.2-0.3 bar for dead end or submerged mode)

Nanofiltration (NF) 500-1000 0.001-0.01

Bacteria, viruses, protozoa, biodegradable organics, organic pollutants, dissolved solids

Reverse Osmosis (RO) 850-7000 0.0001-0.001

Bacteria, viruses, protozoa, biodegradable organics, organic pollutants, organic compounds, dissolved solids

Microfiltration: Microfiltration (MF) is used in advanced treatment application as a

replacement for depth filtration to reduce turbidity, remove residual suspended solids and as a

pre-treatment step for reverse osmosis. Microfiltration membranes have pore size ranging from

0.08-2.0 μm. Boluarte et al. (2016) used hollow fibre microfiltration membrane in their MBR

treatment system for recycling the car wash wastewater, and their system could remove 99.2%

COD, and 100% suspended solids.

Ultrafiltration: Ultrafiltration (UF) is a membrane technique which removes dissolved and

colloidal materials (pore size ranging from 0.005-0.2) (μm) present in the solution at a low

transmembrane pressure (1-5 bar for cross-flow and 0.2-0.3 bar for dead end or submerged

mode). Hamada and Miyazaki (2004) studied the efficiency of using ultrafiltration membrane

to recycle the car wash wastewater and found that it was very effective in removing 100% of

turbidity but only 62% of COD. The MBR with MF membrane can have better removal of

COD compared to UF membrane alone as the former treatment has both biological and physical

treatment.

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Nanofiltration: Nanofiltration membrane is used to reject ions/particles as small as 0.001 μm

dissolved constituents from wastewater such as the multivalent metallic ions which are

responsible for hardness. Boussu et al. (2007) described in their research that hydrophilic

nanofiltration membrane (NF270) has higher water permeability with higher flux compared to

hydrophobic membrane (NFPES10) when nanofiltration was used to retain surfactants and

organic compounds during car wash wastewater treatment.

Moreover, the principal types of membrane modules used for wastewater treatment are; (1)

tubular, (2) hollow fibre, and (3) spiral wound.

Operational parameters for membrane:

Flux:

Flux is an important parameter for the membrane treatment as it shows the efficiency of the

process. Flux is influenced by membrane resistance, operating driving force per unit membrane

area and fouling of the membrane. It is defined as the quantity of permeate passing through a

unit area of membrane per unit time and it is determined by both the driving force and the total

resistance offered by the membrane and the interfacial region adjacent to it. Equation 2.1

defines the flux.

Flux J (m3/m2h) =

--------------------------------------------------- (2.1)

Flow (𝑚3/ℎ) Total membrane area ((𝑚2)

Transmembrane Pressure:

The membrane is used as a selective barrier that allows the passage of certain constituents and

retains other constituents found in the liquid. The driving force for this separation process is

the pressure difference between the feed and permeate side which is called transmembrane

pressure difference or transmembrane pressure (Praneeth, 2014). Three different operating

modes can be used to control the operation of a membrane process with respect to flux and

transmembrane pressure (TMP). These three modes are (1) constant flux in which the flux rate

is fixed and the TMP can vary (increase) with time; (2) constant TMP in which the TMP is

fixed and the flux rate can vary (decrease) with time; and (3) both the flux rate and the TMP

can vary with time. Generally, The TMP is increased with filtration time due to the increase in

the hydraulic resistance of the membrane. At the same time, the declined flux can be recovered

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

by regular backwashing and chemical cleaning. Transmembrane pressure (TMP) can be

calculated by pressure differential across the membrane and indicated by equation 2.2.

Transmembrane pressure,

TMP (Pa)= ½ × [Inlet pressure (Pa)+ Outlet pressure (Pa)]-Permeate pressure (Pa)--------(2.2)

Membrane Fouling:

Membrane fouling is an important consideration in the design and operation of membrane

systems, as it affects pre-treatment needs, cleaning requirements, operating conditions, cost

and performance. Fouling of membrane can occur in three general forms: (i) a build-up of the

constituents on the membrane surface (in the feedwater side), (ii) the formation of chemical

precipitates due to the chemistry of the feed water and (iii) damage to the membrane due to the

presence of chemical substances that can react with the membrane or biological agents that can

colonize on the membrane surface (Metcalf & Eddy, 2003). Membrane fouling can be

influenced by several factors which include:

• Physicochemical properties of the compounds (molecular size, solubility, diffusivity,

polarity, hydrophobicity and charge)

• Membrane properties (permeability, pore size, hydrophobicity and charge)

• Membrane operating conditions (flux, transmembrane pressure and recovery)

• Feed water composition (pH, ionic strength, hardness and the presence of organic

matter).

Three approaches used to control membrane fouling are: (i) pre-treatment of the feed water, (ii)

membrane back flushing and (iii) chemical cleaning of the membrane. Physical cleaning is

supplemented with chemical cleaning to remove irreversible fouling. Rondon et. al (2015)

mentioned in their research that when transmembrane pressure (TMP) reaches 40 kPa the MF

membrane module needs to be cleaned by using deionised water.

Critical Flux:

Critical flux is used to control the fouling of membrane. The concept of critical flux was defined

by Field et al. (1995). Critical flux is that maximum operating flux which does not decline over

time due to fouling of membrane. It can be determined using three different techniques such as

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

(a) common short-term flux step method, (b) improved flux step method and (c) long-term flux

tests. In the common short-term flux step method, flux is increased step-wise and the

corresponding TMP is monitored for a fixed duration. In improved flux step method described

by Van der Marel et al. (2009), membrane is operated at a higher flux, then followed by a fixed

lower flux for equal time durations (less than 1 hour) before it goes to the next higher flux level.

In the long-term flux test, the membrane is operated for a longer period (several days or weeks)

at a constant flux. In all test, the rate of increase of TMP (= dTMP/dt) is observed and the flux

at which there is a significant change in dTMP/dt is considered as the critical flux.

A diagnostic tool for the characterization of membrane foulant is required for efficient

operation of membrane filtration and minimizing the membrane fouling. Scanning electron

microscopy (SEM) can be used to analyse the surface of the fouled membrane and Fourier

transform infrared spectroscopy (FTIR) can be used to analyse the chemical characterization

of membrane foulant. Energy-dispersive X-ray (EDX) can be used for elemental analysis of

the fouled membrane.

Disinfection: Disinfection is used to kill the microorganisms which are not able to be removed

by other treatment processes. Some researchers used chemical agents such as chlorine, ozone

and some researchers used physical agent such as ultraviolet radiation for disinfection. The

type of disinfectant used and the length of contact time are important to assess the quality of

treated water. A study carried out by Etchepare et al. (2014) investigated the efficiency of two

different disinfection processes such as chlorination and ozonation in their vehicle wash

wastewater treatment and found that ozonation can perform better than chlorination as ozone

can degrade the substances present in the cytoplasm and nucleus and causing the death of E.coli

cell.

A summary of different treatment methods used in car wash wastewater treatment is described

in the following Table 2.8.

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Table 2-8 Different treatment methods used in car wash wastewater treatment

Treatment name

Procedure

Reference of application in car

wash wastewater treatment

Screening

A screen is a device with uniform size openings used to retain coarse materials found in the influent

Al-Odwani et al. (2007)

wastewater which can damage subsequent process equipment. It increases the effectiveness of the

treatment process.

Oil/ water separator

Oil/water separator used gravity force to separate oil from water. The difference in densities between

Al-Odwani et al. (2007), Fall et al.

oil and water enables oil to float on top of the water and it can be removed easily.

(2007)

Sedimentation

Sedimentation is used to remove readily settleable solids by reducing the suspended solids.

Tu et al. (2009)

Coagulation and

In the coagulation process, coagulants have been added through rapid mixing to destabilize the particles

Zaneti et al (2011)

flocculation

by blending the chemicals with wastewater. Flocculation is a transport step where the collisions

between the destabilize particles are created through slow mixing to form larger flocs that can be

removed readily by settling or filtration (Metcalf & Eddy, 2003).

Flotation

Flotation is a unit operation used to separate solid or liquid particles by introducing fine gas (usually

Zaneti et al. (2011)

air) bubbles into the liquid phase. These bubbles attach to the particulate matter, and the buoyant force

of the combined particle and gas bubbles is great enough to cause the particles to rise to the surface

(Metcalf & Eddy, 2003). The main advantage of flotation compared to sedimentation is to remove

completely small or light particles within a short time. After the flotation, the particles are collected by

skimming.

Filtration

Filtration is used to remove the suspended solids and particulate material suspended in a liquid by

Tu et al. (2009)

passing the influent through a filter bed comprised of a granular or compressible filter medium. During

its passage the particulate impurities are brought into contact with the surface of sand grains and held

in position there. Those that consist of an inert material are retained until eventually removed during

the cleaning process, while those capable of chemical or biological degradation are converted into

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Treatment name

Procedure

Reference of application in car

wash wastewater treatment

simpler forms that are either carried away in solution or remain, with the inert material, for subsequent

removal (Huisman and Wood, 1974).

Oxidation

Oxidation is used in car wash wastewater treatment to change the chemical composition of certain

Bhatti (2011)

compounds.

Ozonation as oxidation Ozone has considered as an effective oxidizing agent used widely in the chemical water treatment

Tu et al. (2009)

process to decompose the dissolved compounds. In this process, reactive oxygen species is produced

which can react with organic compounds and microorganisms.

Microfiltration

Microfiltration (MF) is used in advanced treatment application as a replacement for depth filtration to

Boluarte et al. (2016)

reduce turbidity, remove residual suspended solids and as a pre-treatment step for reverse osmosis.

Ultrafiltration

Ultrafiltration (UF) is a membrane technique which removes dissolved and colloidal materials (pore

Hamada and Miyazaki (2004)

size ranging from 0.005-0.2) (μm) present in the solution at a low transmembrane pressure (1-5 bar for

cross-flow and 0.2-0.3 bar for dead end or submerged mode).

Nanofiltration

Nanofiltration membrane is used to reject ions/particles as small as 0.001 μm dissolved constituents

Boussu et al. (2007)

from wastewater such as the multivalent metallic ions which are responsible for hardness.

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Conventional treatment and membrane based treatment

As car wash wastewater contains different types of pollutants, a combination of different

treatment processes are required to treat it. Different researchers have used a combination of

the above technologies described in section 2.6 for treating car wash wastewater. Those

technologies can be divided into two groups such as conventional treatment and membrane

based treatment.

Conventional treatment:

Mostly physicochemical processes have been employed in the conventional treatments which

consist of coagulation, flocculation, sedimentation, sand filtration, dissolved air flotation and

chemical precipitation. This is followed by disinfection using either ozone or chlorine.

Etchepare et al. (2014) showed in their research that the treated water quality could not satisfy

all the local discharge standards, though they used coagulant (1200 mg/L tannin, Tanfloc SL)

and flotation with sand filtration. And in the next stage, they used ozonation to satisfy the

standards. In addition, they compared the efficiency of ozonation and chlorination and found

that ozone can perform better than chlorine, but still the average turbidity of the reclaimed

water was 10 NTU which is too high to satisfy the standards described in Table 2.5. Boluarte

et al. (2016) used coagulation-flocculation and ozonation for car wash wastewater treatment

and found that it could remove 88.5% COD and 99.7% turbidity and ozone was very effective

in removing colour. In another research by Bhatti et al. (2011) found that aeration was required

to remove oil and grease due to the high concentration of oil and grease in their wastewater.

Moreover, the comparison of efficiency between natural and commercial coagulants to remove

COD, turbidity, phosphorus from car wash wastewater was carried out by Mohamed et al.

(2014) and they observed that natural coagulants (Moringa Oleifera) performed better in

removing turbidity than commercial coagulants (alum (Al2(SO4)3.14H2O)).

A summary of the various research based on the coagulation, flocculation, sand filtration,

ozonation, chlorination, electrochemical coagulation with anodic oxidation for car wash

wastewater treatment is given in Table 2.9. But many researchers didn’t include the disinfection

process in their treatment system especially the details of the removal percentage of E.coli

bacteria and surfactants are missing.

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Table 2-9 Car wash wastewater treatment systems based on conventional treatment

Technology applied

Remarks

Reference

Influent concentration

Effluent concentration

Removal Efficiency

COD 67%

Coagulation-flocculation, Ozonation,

Boluarte et al. (2016)

Turbidity 99.6%

COD 433 mg/L, Turbidity 1000 NTU

COD 141 mg/L, Turbidity 3.73 NTU

The removal of E.coli, oil-grease, surfactants are not mentioned here. The quantity of sludge generated from coagulation was also not described.

BOD 85%

Flocculation-flotation (FF), Sand Filtration, Ozonation (FFO)

BOD 397 mg/L, COD 683 mg/L

BOD 60 mg/L, COD 96 mg/L

Etchepare et al. (2014)

COD 86%

Average turbidity of reclaimed water is 10 NTU which does not satisfy the standards described in Table 2.5

Turbidity 180.3 NTU

Turbidity 12.4 NTU

Mohamed et al. (2014)

93% (30 mg/L Strychnos Potatorum)

Commercial coagulants (alum and sulphate) and natural ferrous coagulants (Moringa Oleifera and 30 mg/L Strychnos Potatorum)

Natural coagulant showed a great reduction in turbidity but couldn’t satisfy the criteria described in Table 2.5, and the disposal of sludge was a problem

COD 1430 ppm

COD 184 ppm

COD 87.13%

Abdelmoez et al. (2013)

sand sand carbon

Coagulation-flocculation, oxidation, filtration, filtration, activated filtration

This is a combination of 5 different treatment systems so difficult to maintain. Moreover, sludge is a problem which needs to be disposed of and the effluent COD was high to satisfy the standards.

al.

filtration

Zaneti (2011)

(FCF-S) filtration-chlorination

BOD5 53%COD 55%Turbidity 92%

Average turbidity of effluent is 9 NTU higher than the standards. Chlorination is very effective to reduce coliforms.

Flocculation-column-flotation (FCF)-sand FCF-sand (FCF-SC)

BOD5 81 mg/LCOD 213 mg/L, Turbidity 160 NTU

BOD5 38.5 mg/L, COD 96 mg/L, Turbidity 13 NTU

al.

COD 93% Turbidity 94%

Bhatti (2011)

Aeration, coagulation (alum) and 3 mL/L hydrogen peroxide used as an oxidant

COD 1019 mg/L, Turbidity 772 NTU

COD 80 mg/L, Turbidity 33 NTU

Turbidity and COD of the treated water are still high. The removal of bacteria and surfactants are also not mentioned here.

and

Electrocoagulation electrochemical oxidation

Panizza Cerisola (2010)

Need to adjust pH of the solution by adding H2SO4 or NaOH to remove COD.

97% COD removed in 100 min of treatment

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Despite being widely used, these conventional technologies have various disadvantages, such

as (i) generation of large volumes of sludge, (ii) additional waste disposal costs, (iii) require

manual input to remove scum, (iv) cost of different types of coagulant and (v) require pH

control.

Membrane based treatment:

Membrane filtration is a useful technology in treating various kinds of industrial wastewater

such as textile dyeing effluent, oily water, municipal wastewater, wastewater from pulp and

paper industry as well as poultry processing wastewater (Lau et al., 2013, Rondon et al., 2015).

This technology is comparatively new, but it is showing a superior performance in the

wastewater treatment.

Different researchers have started to use membrane technology in their research regarding car

wash wastewater treatment from last few years. Hamada and Miyazaki (2004) used cellulose

acetate ultrafiltration membrane aided by flocculation and activated carbon treatment to recycle

the car wash wastewater. In their study, they showed that a multi blended flocculating agent

(48 wt% bentonite, 48 wt% Al2(SO4)3, 2 wt% sodium alginic acid and 2 wt% cationic

polyacrylamide) was more effective in removing the COD and turbidity compared to individual

flocculating agents. In that research, flocculation treatment was used to remove oily substances

and a great deal of particles. Secondly, the particles and flocs that could not be removed by

flocculation treatment were completely removed by the ultrafiltration (UF) membrane. Finally,

surfactants that can permeate through the membrane were removed by activated carbon

treatment. Another study carried out Li et al. (2007) found that the addition of potassium

permanganate (KMnO4) to coagulant poly aluminium chloride (PAC) was very effective in

increasing the flux by reducing the fouling of ultrafiltration membrane during car wash

wastewater treatment. But this ultrafiltration membrane couldn’t remove sufficient linear

alkylbenzene sulphonates (LAS) as well as odour and colour causing compounds. So, further

treatment with granular activated carbon (GAC) was required to satisfy the water quality

criteria for reuse mentioned in Table 2.5.

Another research showed that nanofiltration membrane NF270 is more efficient than

ultrafiltration membranes such as UF PVDF100 and UF PES30 to treat the car wash wastewater

(Lau et al., 2013) and NF270 could remove 92% of turbidity and 70.9-91.5 % of COD.

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Moreover, a research regarding recycling car wash wastewater was carried out using

Membrane Bioreactor (MBR), and the result was very satisfactory as 99.2% COD was removed

(Boluarte et al., 2016). Hollow fibre microfiltration membrane was used in that study. But that

research was conducted over a short period of time and they did not study about critical flux,

the effects of hydraulic retention time on permeate quality, membrane performance. A

summary of various research based on the membrane technology carried out for the car wash

wastewater treatment is given in Table 2.10.

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Table 2-10 Car wash wastewater treatment methods based on membrane

Technology applied

Influent

Effluent

Removal Efficiency

Remarks

Reference

concentration

COD 99.4%, TSS 100%

Fouling analysis is missing.

MBR, Hollow fibre membrane

COD 776 mg/L, TSS 307 mg/L

COD 5 mg/L, TSS 0 mg/L

Boluarte et al. (2016)

Not available

Surfactants, E.coli bacteria removal efficiency, is missing here.

Lau et al. (2013)

PVDF100 and PES30 Ultrafiltration and NF270 Nanofiltration membranes

NF270 membrane is more efficient than UF PVDF100 and UF PES30. Turbidity: 92% removed COD: 70.9-91.5% removed

Tu et al. (2009)

COD 80-92%, fossil oil and grease 99%, turbidity 95%

COD 10-25 mg/L, fossil oil and grease 4- 20 mg/L, turbidity <2 NTU

Sedimentation, surface degreasing, sand filtration, ozonation, UV irradiation and membrane separation (pore size of 1.2 μm).

COD 50-300 mg/L, fossil oil and grease 500-3000 mg/L, turbidity 20-40 NTU

Though this system can remove a high percentage of fossil oil and grease but could not meet the effluent standards. So, further treatment with activated carbon is required.

Boussu et al. (2007)

Nanofiltration membranes: hydrophilic (NF270) and hydrophobic (NFPES10)

COD 296 (mgO2/L), Nonionic surfactants 50 (ppm) in cyclone

COD 65 (mgO2/L), Nonionic surfactants 1 (ppm) after treating with NF270

Best results with a hydrophilic membrane. Surfactants and other organics removal efficiency up to 95%.

The concentration of surfactants needs to be controlled as it can increase the fouling on nanofiltration membrane.

Not available

The amount of generated sludge is not mentioned

Li et al. (2007)

Hollow Fibre Membrane Aided by KMnO4, Activated Carbon Treatment

COD, BOD, LAS and oil were 33.4 mg/L, 4.8 mg/L, 0.06 mg/L and 0.95 mg/L, respectively

COD 52-62%

COD 5.7-20.5 mg/L, Turbidity: <0.05 NTU

Turbidity 99-100%

Flocculation, ultrafiltration membrane and activated carbon

COD 7.7-41.7 mg/L; Turbidity 4.1-63.5 NTU

Blended flocculating agent can increase the permeation flux compare to individual flocculant

Hamada and Miyazaki (2004)

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Financial Evaluation:

An economic analysis was conducted by Boussu et al. (2008) assuming a hypothetical

automatic car wash with a total consumption of 600 litres a car, 3000 cars a year and 285

working days a year. They carried out a comparison among the car wash centers that are

without treatment systems, with biological treatment systems and with biological and

membrane based treatment systems with respect to the financial scenario. The summary of the

result of financial evaluation is expressed in Table 2-11.

Table 2-11 Summary of the economic evaluation of car wash wastewater treatment

(Boussu et al., 2008)

Installation Costs/Benefits Pay-back Period (years) Amount of water saving per year Total cost (capital + operation) Price (€) Settling tank, oil separator+ Scenario 1: Reuse in prewash Reservoirs pumps, cyclones 39,192 1 10,050 m3 +Energy+ Discharge tax+

Water purchase

Scenario 2: Reuse in Reservoirs, pumps,

prewash + main wash biology+ Energy +

82,504 3 16.050 m3 Discharge tax + Water Installation: Biological purchase treatment

Scenario 3: Reuse in Reservoirs, pumps,

prewash+ main wash+ membrane unit, biology+

rinsing +Energy+ Discharge tax+

125,591 4 17,700 m3 Water purchase Installation: Ultrafiltration

+Biological treatment of

From that analysis, it can be seen clearly that though the installation cost of the membrane

based system is high compare to the other two systems and the payback period is 4 years for

membrane based system. Considering the long-term aspect, it is feasible to implement the

membrane based system as it saves large amounts of water compared to the other two systems.

retentate

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

In conclusion, it can be said that the conventional treatment systems can produce high quality

effluent but it is less efficient than sophisticated membrane based systems.

Proposed research

Compared to conventional treatment technology, membrane based technology can deliver

superior performance by providing an absolute separation of particles and microorganisms.

Based on the literature survey of previous study regarding car wash wastewater treatment, it

was decided to use membrane based technology in this study to treat car wash wastewater. Two

treatment processes were selected in the study, one is ceramic ultrafiltration membrane with

reverse osmosis after coagulation, flocculation, sedimentation and sand filtration and the other

one is enhanced membrane bioreactor (eMBR). The details of the two treatment processes are

given in the following paragraph.

Treatment system 1: Coagulation, flocculation, sedimentation, sand filtration,

ultrafiltration using ceramic membrane and reverse osmosis

Ultrafiltration with ceramic membrane showed a good performance in producing effluent in

different sectors such as sugarcane juice treatment (Jegatheesan et al., 2009). In addition, it can

operate at high flux. But membrane fouling is one of the most widespread problems for

membrane technology. This fouling can be due to the accumulation or adsorption of

contaminants on the membrane surface or within the pores. At the same time, it can decrease

the permeability of the membrane surface while decreasing the quality of product water and

increasing operating pressures. As a result, the useful life of the membrane becomes shorter.

Therefore, many researchers have investigated the procedure to decrease the membrane fouling.

Pre-treatment with coagulation, flocculation, with or without sedimentation followed by sand

filtration has been accepted as an effective solution to control membrane fouling before passing

the wastewater through ultrafiltration.

In coagulation as pre-treatment, the dose of coagulant is critical as overdosing of coagulant can

lead to charge reversal and re-suspension of the colloidal material (Binnie and Kimber, 2009).

Therefore, appropriate dose of coagulant for the treatment should be determined. Most of the

colloidal particles are removed during coagulation but there could be some particles remaining

which can affect the fouling on the ceramic ultrafiltration membrane. So, to remove those

colloidal particles it’s better to pass the supernatant obtained through a sand filtration. A

schematic flow diagram of the first treatment system is shown in the Figure 2.3.

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

In the following sections the detailed theory of coagulation-flocculation, sand filtration,

ceramic ultrafiltration membrane and reverse osmosis are described.

Figure 2-3 A schematic diagram of first treatment system consisting of coagulation-flocculation, sand filtration, ceramic ultrafiltration membrane and reverse osmosis

Pre-treatment with coagulation-flocculation:

Over the last 20-30 years of the 20th century, coagulation and flocculation treatment technology

have been widely used to treat different wastewater (Binnie and Kimber, 2009). In the

coagulation technology, coagulants are added by rapid mixing to destabilize the particles by

blending the chemicals with wastewater (Binnie and Kimber, 2009). Flocculation is then

followed which is a transport step where the collisions between the destabilize particles are

induced by slow mixing which allows to form larger flocs that can be removed readily by

settling or granular filtration (Metcalf & Eddy, 2003). Four main methods in coagulation theory

attributed to destabilize colloidal particles are double layer compression, charge neutralization,

entrapment in the precipitate and particle bridging. If the granular filtration is followed by

settling then the filtration process is called as conventional filtration, and if the flocculated

wastewater is directly sent for filtration, then the filtration process is called direct filtration.

Direct filtration is suitable when the suspended solids concentration is low in the raw

wastewater. In granular filtration, sand is generally used as filter medium.

Granular filtration using sand as filter medium:

Sand filtration has been used as a pre-treatment step for membrane filtration by different

researchers. In the sand filtration, several complex forces are involved in capturing the

impurities through different types of transport mechanisms such as straining, sedimentation,

inertial and centrifugal forces, diffusion, mass attraction and electrostatic and electrokinetic

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

attraction. Initially, the particles larger than the pore space of the filtering medium are strained

out mechanically, and particles smaller than the pore space are trapped within the filter by their

contact with filter grains. The main forces that can hold particles during contact with the sand

grains are (a) electrostatic attraction, (b) Van der Waals force, and (c) adherence (Huisman and

Wood, 1974). During this contact, some aggregation takes place. When agglomerated particles

become large enough to be retained by the screening mechanism they deposit on to filter grains.

The advantage of the sand filter is that it can produce better treated quality water by removing

particles and the construction and operation of the sand filter are comparatively easy. Although

the effluent from the sand filter will be free of suspended solids, some residue will remain

which can be removed by ceramic ultrafiltration membranes and reverse osmosis. However,

the residual suspended solids will foul the membrane along with other dissolved constituents

present in the sand filter effluent.

Ultrafiltration using ceramic membranes:

Ceramic membrane has superior chemical, thermal and mechanical stability compared to

polymeric membranes (Lee and Cho, 2004). It can exhibit good stability to organic media and

resistance to bacterial action. Moreover, it has a significant advantage that it has long and

reliable lifetime to reduce membrane cost compared to polymeric membrane (Muthukumaran

and Baskaran, 2014). Ceramic UF can be operated at either dead end or cross flow filtration

mode. In a ceramic UF membrane, the turbid fluid goes through a single channel or multiple

channels at a high velocity. Driven by transmembrane pressure (TMP), the liquid with micro-

molecules which are smaller than the pore size of membrane pass through the membrane and

the solid and big molecules are rejected in retentate.

Reverse osmosis:

Reverse Osmosis (RO) membrane is a dense membrane which has no defined pores. So, the

permeation is slower, and rejection is not a result of sieving. The separation mechanism of the

reverse osmosis is solution-diffusion. High pressure is required for this low permeability

membrane to produce permeate. The major drawback of RO systems is its high-power

consumption due to the pumping pressure and membrane restoration. The RO systems are used

to remove soluble ions, dissolved solids, and organic materials from the high-quality tertiary

effluent to polish final effluents for reuse or for groundwater recharge. It is widely used in

ultrapure water production, desalination, and municipal waste water treatment. But extensive

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

pre-treatment and periodic cleaning is required for maintaining high water flux levels through

RO membranes. These systems are used in combination with other removal techniques to

obtain higher efficiency.

Treatment system 2: Enhanced Membrane Bioreactor (eMBR)

Membrane bioreactor (MBR) technology has become widely accepted and used for the

treatment of municipal and industrial wastewater from last few decades. This technology has

been promising as it can produce high-quality effluent compared to conventional treatment. In

this research, eMBR is used as the second treatment system to treat car wash wastewater. The

details of MBR and eMBR are given below.

Membrane Bioreactor (MBR):

Membrane bioreactor (MBR) is a combination of biological reactor and membrane. Here

bioreactor acts as a biological treatment process and the membranes used in the filtration

process to reject the solid materials and microorganisms generated by the biological processes.

MBR is becoming the first choice for wastewater treatment because of its ability to work at

low food to microorganism ratio (F/M) by increasing high mixed liquor suspended solids

(MLSS) in biological reactors (Hai et al., 2014). High solids retention time (SRT) allows slow

growing microorganisms such as Nitrosomonas bacteria that could degrade persistent organic

pollutants to grow. This is not possible in a conventional activated sludge process.

Two different membrane configurations are available in MBR. The first one is called

submerged or immersed MBR and second one is called side stream MBR (Hai et al., 2014). In

submerged MBR, the membrane module is directly immersed into the bioreactor, and negative

pressure is applied using a vacuum pump to suck the permeate through the membrane. This

type of MBR is widely used because of its compactness and low energy requirements.

Alternatively, less membrane is required for side stream MBR, but it requires more energy for

pumping and recirculating the MLSS. Moreover, it needs additional space.

Enhanced Membrane Bioreactor (eMBR):

Enhanced Membrane Bioreactor (eMBR) comprises of an anaerobic reactor (AR1), an anoxic

reactor (AR2), an aerobic membrane bioreactor (AMBR) and a UV-disinfection unit. eMBR

can remove not only organic substances but also nutrients. This system is called the three stage

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

(Anaerobic zone, Anoxic zone, and Aerobic zone) Bardenpho process or A2/O process (Hai et

al., 2014). The schematic diagram of eMBR is given in Figure 2.4. The advantage and

disadvantage of eMBR, the role of microorganisms, anaerobic reactor, anoxic reactor, AMBR

and other parameters in eMBR process are described in the following sections.

Figure 2-4 A schematic diagram of eMBR

1. Feed tank; 2. Anaerobic tank; 3. Anoxic tank; 4. AMBR tank; 5. UV Lamp; 6. Permeate tank; 7. Membrane module; 8. Feed pump; 9. Recirculating pump; 10. Suction pump; 11. Stirrer; 12. Bioballs in anoxic and anaerobic tank; 13. Diffuser; 14. Pressure gauge; 15 Level meter.

Advantages and disadvantages of eMBR:

Enhanced membrane bioreactor is a good option to treat different types of wastewater as it has

capacity to remove various types of pollutants (Rondon et al., 2015). It has many advantages,

such as (1) higher volumetric loading rates and thus shorter hydraulic retention times, (2) longer

solids retention time (SRT) is resulting in less sludge production, (3) operating at low dissolved

oxygen (DO) concentrations with potential for denitrification in long SRT designs, (4) high-

quality effluent in terms of low turbidity, bacterial count, total suspended solids (TSS) and

biochemical oxygen demand (BOD) and (5) less space required as secondary clarifier processes

are eliminated (Praneeth, 2014). However, its disadvantages include high capital costs, limited

data on membrane life, potentially high cost incurred for periodic membrane replacement,

higher energy costs and membrane fouling.

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Microorganisms:

Microorganisms play a vital role in biological treatment systems as they can degrade the

organic and inorganic compounds (in wastewater). But to ensure the growth of microorganisms,

the availability of nutrients should be maintained during the treatment process. The organic

and inorganic compounds present in the wastewater are used as nutrients for the growth of

microorganisms. Carbon dioxide or organic wastes are used as carbon for cell synthesis, and

light or chemical compounds are used as the source of energy (Hai et al., 2014). The

classification of microbes depends on the carbon and energy sources such as photoautotrophs

(light as energy source and carbon dioxide as carbon source), photoheterotrophs (light as

energy source and organic compounds as carbon source), chemoautotrophs (chemical

compounds as energy source and carbon dioxide as carbon source) and chemoheterotrophs

(chemical compounds as energy source and organic compounds as carbon source).

From the Metcalf & Eddy (2003) it was found that the composition of microorganisms is

C5H7NO2 and to maintain that composition of cell biomass, 12.4% by weight of Nitrogen (N)

is required; the Phosphorus (P) requirement is 1/5 of the N (Metcalf & Eddy, 2003). Table 2.12

gives the ratio of COD:TN:TP found from previous studies when treating different types of

wastewater by MBR. It can be said that the maximum and minimum ratio of COD:TN:TP are

273:2.14:1 and 10-24:>4:>1 respectively according to the Table 2.12.

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Table 2-12 The ratio of COD:TN:TP in different wastewater treated by MBR

Wastewater source

COD:TN:TP ratio

MLSS

References

Location where the ratio of COD:TN:TP is measured

MBR

6700:1100:150 (kg/d) (44.7:7.3:1)

Hai et al. (2014)

Settled sewage of mainly domestic origin (10% Industrial sewage)

Municipal/Industrial

MBR

50-120: >20: >5 (10-24:>4:>1) (mg/L)

Hai et al. (2014)

Domestic

MBR

COD:TN ratio 1008:99 (10.2:1) (kg/d)

8 kg/m3

Hai et al. (2014)

COD:TN ratio 1591:71 (22.4:1)

AMBR 4.04 g/L

Feed (100% Synthetic waste water)

Car wash waste water

Michael Andersen (2015)

COD:TN ratio 1693:27.8 (619:1)

AMBR 0.471 g/L

Feed (25% Car wash waste water)

COD:TN ratio 776:4.5 (170.5:1)

AMBR 3.25 g/L

Feed (100% Car wash waste water)

Dye wastewater

Feed (50 mg/L RTB-1330)

2334:4.8:2.7 (107.6:1.7:1) (mg/L)

AMBR 3.115 g/L

Rondon et al. (2015)

Municipal wastewater

Chae et al. (2006)

13750±170 :83±26:36±15 (13920:109:51 or 13580:57:21) (273:2.14:1 or 646:2.72:1)

5.7 g/L (Anoxic) and 2.2 g/L (Oxic)

Sludge

Anoxic (Vertical submerged membrane bioreactor (VSMBR)) Anoxic

100:10:2 (50:5:1)

Lee et al. (2003)

Kraft evaporator condensate Anaerobic

10000±500:2.6:1

Lin et al. (2009)

A2O Process

COD: P ratio 34-43

Metcalf & Eddy (2003)

C5H7NO2, for the composition of cell biomass about 12.4% by weight of Nitrogen will be required and Phosphorus required will be 1/5 of N.

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Anaerobic reactor:

Phosphorus removal is essential to avoid eutrophication in receiving water bodies. An

anaerobic tank should be introduced in front of the aeration tank for phosphorus removal. In

the anaerobic zone, the Phosphorus Accumulating Organisms (PAOs) take up and store volatile

fatty acids (VFAs) as carbon compounds such as poly-b-hydroxybutyrate (PHB) and the

required energy was provided by the cleavage of another storage product, the inorganic

polyphosphate granules. The PAO use the internally stored PHB as a carbon and energy source

and take up all the phosphate released in the anaerobic zone and additional phosphate present

in the influent wastewater to renew the stored polyphosphate pool (Jeyanayagam, 2005). A

schematic diagram of biological phosphorus removal is shown in Figure 2.5.

Figure 2-5 A schematic diagram of Biological Phosphorus removal

(Jeyanayagam, 2005)

Anoxic reactor:

To remove nitrogen from wastewater both anoxic and aerobic conditions are required. In the

anoxic tank, denitrification is carried out by heterotrophic bacteria, and organic substrate is

required as electron donor. So, the anoxic tank is required to place in front of the aerobic tank

to utilise the organic substrate present in the influent.

The following chemical reaction will take place in the anoxic bioreactor.

−)

𝑀𝑖𝑐𝑟𝑜𝑜𝑟𝑔𝑎𝑛𝑖𝑠𝑚 → 𝑁2

𝑂𝑟𝑔𝑎𝑛𝑖𝑐 𝐶𝑜𝑚𝑝𝑜𝑢𝑛𝑑𝑠 + 𝑁𝑖𝑡𝑟𝑎𝑡𝑒 (𝑁𝑂3

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Aerobic Membrane Bioreactor (AMBR):

Aerobic Membrane Bioreactor (AMBR) is a combination of a bioreactor and a membrane. In

this research, internally submerged MBR was used. An air diffuser is introduced in the

bioreactor (at the base of the membrane module) to maintain the dissolved oxygen

concentration by supplying air and to assist in reducing the fouling. The water level in the

AMBR is maintained at a constant level by introducing a level meter. This helps to keep the

hydraulic retention time (HRT) of the AMBR at a prescribed value.

In this research, hollow fibre microfiltration membrane was selected as it requires less pressure

and has satisfactory performance to remove the bacteria, suspended solids. The SEM picture

of the membrane which was used in this research is shown in the Figure 2.6, and in the Table

2.13 membrane characteristics of the hollow fibre membrane are given.

Figure 2-6 SEM picture of Hollow Fibre Membrane

Table 2-13 Membrane Characteristics

Hydrophilic Polyethersulfone (H-PES)

Material

Thread type

Hollow fibre

Thread count

Thread diameter (mm)

1.2

Thread pore size (μm)

0.1

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

In the AMBR, the organic compounds are oxidized to simple molecules such as CO2 and water

while generating biomass. Autotrophic bacteria play a vital role in removing nitrogen. In the

first stage, it oxidizes ammonia to nitrite, and in the second stage, another group of autotrophic

bacteria oxidizes nitrite to nitrate. During recirculation, this nitrate goes into the anoxic tank

and produces nitrogen gas.

Organic Compounds + 𝑂2 → CO2 + H2O (MBR)

NH4

++1.5𝑂2 → N𝑂2

−+2H+ + H2O (stage 1) (Nitrosomonas-bacteria)

NO2

-+0.5𝑂2 → N𝑂3

− (stage 2) (Nitrobactor-bacteria)

NH4

++2𝑂2 → N𝑂3

− +2H+ + H2O (combination of stage 1&2)

Moreover, in the aerobic reactor, the PAO use the internally stored PHB as a carbon and energy

source and consume the phosphate released in the anaerobic zone and the additional phosphate

present in the wastewater.

Oxygen requirement:

Oxygen plays a vital role in eMBR system as it is required to oxidize the biodegradable organic

compounds as well as ammonia-nitrogen. Moreover, oxygen is an essential part for the

respiration of microorganisms. To supply the oxygen, an air diffuser is installed at the bottom

of the AMBR reactor. This air diffuser helps to maintain the dissolved oxygen concentration

in the aeration tank by providing adequate mixing for the suspended solids (Metcalf & Eddy,

2003). The required amount of oxygen for biological nutrient removal system can be computed

by the following formula 2.4:

kg O2 required/d = Ka × kg BOD removed per day + 4.57 × NH3-N removed +Kb × Volume of

the aeration tank × MLSS ------------------------------------------------ (2.4)

where, Ka (carbonaceous oxygen demand) =0.65 and Kb (respiration oxygen demand) =

0.067/d. (Hai et al., 2014)

Hydraulic retention time (HRT):

Hydraulic retention time is an important parameter for eMBR. It is an indication of sufficient

time provided for the wastewater to stay in all three compartments to complete the biochemical

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

reactions to remove the organics and nutrients of the wastewater. It is calculated by dividing

the volume of reactor by the flow rate as indicated by equation 2.5.

𝐹𝑙𝑜𝑤 𝑟𝑎𝑡𝑒 (

HRT (day) = 𝑉𝑜𝑙𝑢𝑚𝑒 (𝑚3) -------------------------------------------------------------------------- (2.5) 𝑚3 ) 𝑑𝑎𝑦

Solids retention time (SRT):

Solids retention time is the most critical parameter for biological activity as it affects the

treatment process performance, the volume of the aeration tank, amount of sludge generation

and oxygen requirements. It is found that the longer SRT favours the development of slow

growing bacteria and presence of diverse microbial communities and adaption of these

communities to degrade specific organic compounds (Hai et al., 2014).

Food to Microorganism ratio (F/M ratio):

Food to microorganism ratio is an important parameter for the design of eMBR. F/M ratio can

be determined by the following equation 2.6.

F/M =QSo/(V*MLSS) ------------------------------------------------------------------------------(2.6)

Where, F=Food or BOD concentration; M=Microorganism; V=Volume of reactor, m3; MLSS=

mixed liquor suspended solids, mg/L; So=Substrate concentration, mg/L; Q=Flow rate (L/day)

Literature survey shows that the lower the F/M ratio higher the efficiency of biochemical

oxygen demand (BOD) removal. The F/M ratio can be made lower in two different ways, one

is by increasing the volume of the aeration tank which is not economical always and another

way is by increasing the MLSS. As the membrane in the eMBR is rejecting the solids, the

MLSS can be increased. In this way, F/M ratio can be controlled better in an eMBR, and

consequently better removal of BOD can be expected compared to that from a conventional

treatment (Hai et al., 2014).

Ultraviolet (UV) Disinfection Unit:

Ultraviolet (UV) radiation system is used to disinfect the wastewater. A UV unit requires less

space than chlorine disinfection unit, and it has no residual toxicity. Further, it does not increase

TDS level in the treated effluent. The effectiveness of UV disinfection is based on the UV dose

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

to which the microorganisms are exposed. The UV dose D (mJ/cm2 or mW.s/cm2) is defined

as follows:

𝐷 = 𝐼 × 𝑇 -----------------------------------------------------------------------------------------------(2.7) Where, I= UV intensity, mW/cm2

T=exposure time, in second

The UV energy penetrates the outer cell membrane of the microorganism and passes through

the cell and disrupts its DNA which is responsible for reproduction (Aquafine Corporation

“Ultraviolet Systems” brochure, n.d).

Conclusion

Recycling the car wash wastewater is the main aim in this research. Therefore, an extensive

literature review is done which consists of pollutants of car wash wastewater with impacts on

the environment, the current disposal methods of wastewater used in car wash centers and the

details of different technologies used by different researchers for treating the car wash

wastewater. After evaluating this literature review, two membrane based technologies were

selected for this research, and the details of two selected membrane based technologies are

described in this chapter.

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Chapter 3

3 Recycling of car wash wastewater treated by Ceramic Ultrafiltration and

Reverse Osmosis Membranes

Introduction

Wastewater generated at car wash centers is one of the primary concerns for the environment

as it contains various pollutants which can pose a threat to the environment if it goes to the

sewerage system without any treatment. Recycling this wastewater can be a potential solution.

By recycling, pollutants can be separated from the water to reduce the impact on the

environment, and the treated water can be reused for washing cars back in the car wash centers.

In this research two different types of treatment systems for recycling the car wash wastewater

were studied in the laboratory: treatment system 1 - ceramic ultrafiltration membrane and

reverse osmosis and treatment system 2 - enhanced membrane bioreactor (eMBR). The details

of system 1 are described in this chapter.

Materials and Methods

Car wash wastewater was collected from different car wash centers, and the wastewater

parameters were analyzed. Jar test was conducted for each sample to find out the optimum dose

of coagulant. The required amount of coagulant was added to the wastewater to coagulate and

subsequently flocculate suspended particles present in the wastewater. When the flocs were

settled down, the supernatant was collected and filtered with a sand filter. The sand filter

effluent was passed through the ceramic ultrafiltration membrane followed by reverse osmosis

membrane. The quantity of the sludge produced from coagulation/flocculation and the amount

of concentrate generated by both membranes were quantified. A schematic diagram of the

treatment system 1 is shown in Figure 3.1 and described in the following subsections.

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Figure 3-1 A schematic diagram of treatment system 1 comprising coagulation, flocculation, sedimentation, sand filtration, ceramic ultrafiltration and reverse osmosis membrane

Sample collection and water quality analysis

Car wash wastewater samples were collected from a hand car wash center in Melbourne

according to the Standard Method for Examination of Water and Wastewater (APHA, 1999)

(1060 -collection and preservation of samples) and stored at 4 ͦC. Samples were brought back

to the room temperature (22±2 ͦC) before passing through the treatment system 1 (as shown in

Figure 3.1). The samples were collected after each treatment process. Those samples along

with the raw car wash wastewater sample were analysed for chemical oxygen demand (COD),

nitrite (NO2

-), nitrate (NO3

-N), ammonia (NH3-N), total nitrogen (TN), total phosphorus (TP),

pH, dissolved oxygen, electrical conductivity (EC), total dissolved solids (TDS), particle sizes,

- were measured by

heavy metals (Cu, Zn) and turbidity. COD, TP, TN, NH3-N, NO3

-N, NO2

colorimetric techniques using a HACH spectrophotometer (Model DR/4000U) according to

the methods 8000, 10127, 10072, 10031, 8039 and 8153, respectively, described in HACH

protocols. The collected samples were filtered through 0.45 μm filter (mixed cellulose esters,

Advantec, Japan) before the analysis. Every analysis of each sample was done twice and the

average value has been reported in the results. Particle size analyses for the raw car wash

wastewater and permeate from ceramic ultrafiltration membrane were carried out using

Mastersizer Particle Size Analyser (Malvern Mastersizer 3000). The turbidity was measured

using a turbidity meter (HACH, 2100AN) for each sample. The pH, EC, and TDS of the sample

were measured twice for each sample using pH meter (Mettler Toledo), EC meter (HACH,

CDC 401) and TDS meter (HACH SENSION MM150), respectively. Heavy metals such as

copper (Cu) and zinc (Zn) were determined by using atomic absorption spectroscopy

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

(VARIAN AA240 FS). Heavy metal analysis was carried out in triplicate for each sample and

the average value has been reported in the results.

Experimental set-up for the treatment system 1

Coagulation-flocculation

The collected raw car wash wastewater was firstly treated with coagulation. Coagulation was

performed using a conventional jar test apparatus consisting of 5 beakers each with a volume

of 2 L (Velp Scientifica JLT 6). Alum (Al2(SO4)3.14 H20) and ferric chloride (FeCl3)

coagulants (purchased from Science Supply Australia) were applied to wastewater samples

during jar test. The characteristics of those coagulants are given in Table 3.1. Initially the

experiments were conducted using a wide range of different doses (15mg/L to 500 mg/L) of

Ferric chloride. The turbidity of the supernatant was checked after each experiment. After

comparing the results of the turbidity of the supernatant, the suitable range was found between

35mg/L to 55 mg/L. During the jar test experiments after rapid and slow mixing, the samples

were allowed to settle down for 30 minutes; the supernatants were collected for measuring the

turbidity. Similar procedure was followed for different doses of (15, 20, 30, 40 and 50 mg/L)

alum (Al2(SO4)3.14 H20) coagulant. After comparing the results of turbidity of the supernatant

from different doses of FeCl3 and alum, it was found that 45 mg/L of FeCl3 at 300 rpm of rapid

mixing for 1 minute and 30 rpm of slow mixing for 30 minutes showed a better result (with

respect to the turbidity of the supernatant) than alum. These coagulation tests were performed

without any pH adjustment. So, 45 mg/L FeCl3 coagulant was used to treat the car wash

wastewater for rest of the experiments. This supernatant from the jar test was collected and

passed through the sand filter.

Table 3-1 Characteristics of coagulants used in this study

Common name/ Chemical Molecular Specific gravity chemical name formula weight

Alum/ Aluminium 595 Approx. 1.3 (bulk Al2(SO4)3.14 H20

Sulfate density) 1.32 at 15ͦC

Ferric Chloride 162 Approx. 1.45 FeCl3

Ref: Binnie and Kimber (2009)

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Sand Filtration

In this study, slow sand filter with sand as uniform mono-medium (uniformity coefficient 1.33)

was used to treat the supernatant collected from the jar test. The grain size analysis obtained

by sieving of the sand filter is given in Table 3.2. The height and the area of the slow sand filter

were 0.235 m and 0.00442 m2, respectively (The height of slow sand filter was chosen based

on the configuration of the available sand filter column. The largest depth of sand filter was

chosen to ensure the removal of all impurities from wastewater). The supernatant collected

from coagulation treatment was fed to the sand filter continuously through a pump. A

downflow velocity of 0.35 m/s was maintained during the filtration. The flow velocity varied

from 0.302 m/s to 0.226 m/s when the filter was run for 90 minutes. The turbidity of the effluent

was checked every 5 minutes, and periodic backwash with tap water was carried out when an

increase in turbidity was observed. The effluent was collected from sand filtration for water

quality analysis and to treat with ceramic ultrafiltration membrane.

Table 3-2 Grain size analysis of the sand used in filtration

Openings Cumulative Cumulative Sieve Retained (g) Retained % Passing Smaller Larger Retained (%) Micron (%) (mm) (mm)

2000-1000 1.000 2.000 0.15 0.06 0 100

1000-500 1.000 0.500 43.56 16.24 16 84

500-250 0.500 0.250 94.43 35.20 51 49

250-125 0.250 0.125 125.42 46.75 98 2

125-44 0.125 0.044 4.71 1.76 100 0

Total: 268.27

Ceramic Ultrafiltration Membrane

In this research, the ceramic ultrafiltration membrane with 0.02 µm (area 0.12 m2) was used to

filter the car wash wastewater (feed) after treated by sand filtration as mentioned in the previous

section. The experimental setup of the system is shown in Figure 3.2. The ceramic membrane

had tubular configuration consisting of 19 channels and made of zirconia oxide (manufactured

by Jiangsu Jiuwu HiTech, Nanjing, China). A cooling system was installed with the feed tank.

The effluent collected from the sand filtration was placed in the feed tank and circulated

through the membrane module by a centrifugal pump. The valves before (V1) and after (V2)

in (as shown in Figure 3.2) the membrane module were adjusted to obtain the desired operating

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

transmembrane pressure and cross-flow velocity. The recirculation was carried out for the first

30 minutes of filtration. After 30 minutes, the retentate was recycled to the feed tank while the

permeate was collected in a beaker. The volume of the permeate was recorded in every 10

minutes to calculate the flux. The transmembrane pressure was maintained at 2.5 bar. When

the filtration was completed, the membrane was rinsed with de-ionized water and cleaned with

40% Sodium hydroxide (NaOH).

Figure 3-2 Experimental set-up of ceramic ultrafiltration membrane to filter pre-treated car wash wastewater

Reverse Osmosis

A laboratory-scale Reverse Osmosis (RO) filtration system manufactured by Jiangsu Jiuwu

Hitech Co. Ltd. was used to treat the effluent collected from ceramic ultrafiltration membrane.

This RO filtration system was attached to a 30 L feed tank, and a heat exchange jacket was also

connected to the feed tank. A spiral wound RO membrane (SG1812C-28D) manufactured by

GE Water & Process Technologies was used, and the specification of the system is shown in

Table 3.3. The schematic diagram of this RO experiment is shown in Figure 3.3. Before starting

the test, RO membrane was cleaned with 40% sodium hydroxide (NaOH) according to the

procedure given in the RO filtration system manual.

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Table 3-3 Properties of reverse osmosis membrane

Property SG 1812C-28D (RO)

Active area (m2) 0.37

pH range 3-10

Maximum pressure (kPa) 4137

After placing the influent in the feed tank, it was fed through the membrane at 10 bar

transmembrane pressure. During this experiment, the power was supplied at 27.2 Hz. The

permeate from the RO membrane was collected in a beaker, and the volume was recorded in

every 5 minutes to calculate the flux. The retentate was returned to the feed tank. The pH and

turbidity of the permeate were checked in every 10 minutes, and EC of the permeate was

checked in every 5 minutes. The experiment was run for 118 minutes, and the average flow

rate was 3.8 L/h. The permeate from RO membrane was collected for analysis.

Figure 3-3 Experimental set up of reverse osmosis system to treat pre-treated car wash wastewater

Results and discussion

Obtaining high quality recycled water for the reuse in car wash stations is the primary objective

of this study. Therefore, the raw or untreated car wash wastewater quality was analysed initially

as described in section 3.3.1. During the treatment system-1, the collected car wash wastewater

passed through four different treatment step. The progress of each treatment step was observed,

and the findings such as; the effect of coagulant doses on turbidity removal from the car wash

wastewater is described in section 3.3.2, the changes to flux and other parameters during

ceramic ultrafiltration and reverse osmosis and overall the effects of each treatment step on

wastewater quality are described in sections 3.3.3 to 3.3.6.

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Raw car wash wastewater quality analysis

The analysis of raw car wash wastewater showed that the raw car wash wastewater quality

varied with each collection and the point of collection (at the same car wash center). A

summary of water quality of the collected wastewater from the same car wash center is given

in Table 3.4. It can be seen from Table 3.4 that the turbidity of raw car wash wastewater was

very high (763 NTU) in December 2015 compared to that collected in March 2016. This is a

seasonal effect, and Tu et al. (2009) mentioned that in the summer season the concentration of

turbidity increases with increase in the rate of evaporation of water. The change in total

phosphorus of two samples varied significantly (from 0.24 mg/L to 11.3 mg/L). The particle

size varied with the point of collection of the same car wash center as the samples collected

from the upper tank (after grit removal) had particles with smaller sizes compared to samples

collected from an underground reservoir. The car wash wastewater collected on March’2016

was used as a feed solution in treatment system 1.

Table 3-4 Car wash wastewater quality collected at different times

Car wash wastewater quality

Point of collection Underground tank Upper tank (after grit removal)

Collected on 4/3/2016 Collected on 3/12/2015 Parameter

pH 6.42 4.66

EC (µs/cm) 404 509

TDS (mg/L) 259 326

Temp (°C) 18.9 8.8

Turbidity (NTU) 522 763

COD Total (mg/L) 295 471.5

Total Ammonia (mg/L) 9.5 0.8

Total Nitrogen (mg/L) 19.5 3

Total Phosphorus (mg/L) 0.32 11.3

Particle Size Dv (10) (µm) 5.18 4.9

Particle Size Dv (50) (µm) 11.4 11.3

Particle Size Dv (90) (µm) 30.1 21.2

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Coagulation-flocculation

Collected car wash wastewater was first treated with coagulation and different doses of ferric

chloride (FeCl3) and alum (Al2(SO4)3.14 H20) coagulants used in jar tests. After coagulation

test, the supernatant was collected to check the turbidity. The result is compared between

coagulant doses and the turbidity of the supernatant as shown in Figure 3.4 and Figure 3.5.

Figure 3-4 Turbidity of supernatant after jar test with different doses of FeCl3 as coagulant

It was observed from Figures 3.4 and 3.5 that ferric chloride could reduce the turbidity better

than alum and 45 mg/L FeCl3 coagulant dose was the optimum dose to treat the car wash

wastewater. When ferric chloride coagulant was added to the car wash wastewater then

following reaction occurred and Fe(OH)3 precipitated:

2 FeCl3 + 3 Ca(HCO3)2 = 2 Fe(OH)3 ↓+ 3 CaCl2 +6 CO2

Figure 3-5 Turbidity of supernatant after jar test with different doses of alum as coagulant

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

The overall results suggest that coagulation (pre-treatment) with FeCl3 may be effective in

decreasing the effects of fouling of membrane, but after particle size analysis, it was found that

there were still some particles present in the supernatant.

Sand filtration

During sand filtration, the turbidity of the effluent was checked in every 5 minutes. The C and

Co are the turbidity values of the effluent and the influent, respectively, in NTU units. It was

observed in Figure 3.6 that in the initial stage the C/Co was high due to some impurities in the

sand bed, but it decreased over the time. However, after 80 minutes of continuous filtration,

the ratio of the C/Co started to increase which indicated the turbidity breakthrough. Then

backwashing of the filter was carried out. During filtration, the particles arriving near the filter

grains are attached to them due to the adhesive force which is a resultant of the following

surface forces: the London-van der Waals force, the electric double layer force, the hydration

strength and the Born repulsion force (Jegatheesan and Vigneswaran, 1997). As those particles

start to cover the surface of filter grains, so it is useful to evaluate the surface coverage of filter

grain during filtration to understand the interaction between the particles present in the water

and the filter grains. For evaluating the specific surface coverage of filter grains during

filtration, particle size analysis was done for the influent and effluent during sand filtration

experiment.

Figure 3-6 Removal of particles from car wash wastewater during sand filtration

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

During filtration, the surface of the filter particles is covered by different sizes of particles and

the number concentration of particles in the influent and effluent can be determined by using

the following formulas.

------------------------------------------------------------------------------------- (3.1)

𝑁0 =

3𝜌

(

𝐶0 )𝜋𝑎𝑝

4 3

Since Co/𝜌 = Vo, the equation can be rewritten as

𝑁0 =

3 ------------------------------------------------------------------------------------------ (3.2)

(

𝑉0 )𝜋𝑎𝑝

4 3

𝑁𝑒𝑛𝑑 =

3 --------------------------------------------------------------------------------------- (3.3)

𝑉𝑒𝑛𝑑 4 )𝜋𝑎𝑝 ( 3

Here C0 and C is the mass concentration of particles in the influent and effluent,

𝜌 =Density of particles,

N0 and 𝑁𝑒𝑛𝑑 is the number concentration of particles per mL influent and effluent (after 90

minutes filtration) sample,

V0 and 𝑉𝑒𝑛𝑑 is the percentage of volume of particles (with specific sizes) per mL influent and

effluent (after 90 minutes) sample. It is calculated from the particle size analysis and suspended

solids of the influent and effluent sample.

So, the ratio of Nend/N0 after 90 minutes of filtration was determined from equations 3.2 and

3.3. But the number of the concentration of particles at the beginning (at 0 minutes) of the

filtration was not analysed. Therefore, the ratio of 𝑁𝑖𝑛/N0 at the beginning of the filtration time

was determined from Figure 3.6 assuming that (𝐶𝑖𝑛/C0) t=0 = (𝑁𝑖𝑛/N0) t=0.

The specific surface area coverage by particles at time Δt

---------------------------------------(3.4)

= the surface area of particles retained in a unit bed volume in Δt total surface area of collectors in unit bed volume

The specific surface area coverage by particles at time t from the beginning of the filtration can

be computed using the following equation:

(𝜋𝑎𝑝

--------------------------------------------------------------------- (3.5)

= {

) 𝑑𝑡

𝑡 } ∫ (1 − 0

2)𝑈𝑁0𝑎𝑐 [3𝐿(1−𝜖)]

𝑁 𝑁0

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

where, 𝑎𝑝 is the radius of particles

𝑎𝑐 is the radius of collectors (here collector is sand particle and radius of sand particle is

determined by grain size analysis shown in Figure 3.7) =0.150 mm

U=filtration velocity= 0.302 m/s

L=length of filter bed= 0.235 m

𝑁0= Number concentration of particles per mL of influent entering the sand filter

𝑁𝑖𝑛= Number concentration of particles per mL effluent at the beginning of filtration

𝑁𝑒𝑛𝑑= Number concentration of particles per mL effluent after 90 minutes of filtration

𝜖 = porosity of filter bed = 0.40.

part of equation 3.5 can be obtained by the shaded area (ABD1) shown in

) 𝑑𝑡

𝑡 The ∫ (1 − 0

𝑁 𝑁0

Figure 3.8.

Shaded area=(1 − 𝐵) × 𝑡 +

× 𝑡 × (𝐵 − 𝐴) (when B>A)

Shaded area=(1 − 𝐴) × 𝑡 +

× 𝑡 × (𝐴 − 𝐵) (when A>B)

Here A= the ratio 𝑁𝑖𝑛/N0 at beginning of filtration

B= the ratio 𝑁𝑒𝑛𝑑/N0 at 90 minutes of filtration

t= filtration time (90 minutes)

Figure 3-7 Grain size distribution curve of sand filter particles

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

The detailed calculations of specific surface coverage by different particles during sand

filtration (particle sizes ranging from 7.64 μm to 454 μm) is given in Table 3.5. The particles

larger than 454 μm have less specific surface area coverage (< 0.0001) during filtration, and

therefore it was not included in Table 3.5.

Figure 3-8 Area calculation by particles for surface area coverage

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

*It was assumed that (𝐶𝑖𝑛/C0) t=0 = (𝑁𝑖𝑛/N0) t=0

The relationship between the surface area coverage and the particle size is shown in Figure 3.9.

It can be observed from Figure 3.9 that the surface coverage is higher for the smaller particles

(<76 μm) compared to larger particles as the number concentration of smaller particles was

higher in the influent.

Table 3-5 Surface area coverage by different particles during sand filtration

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Figure 3-9 Specific surface area coverage by various particles during sand filtration

Ultrafiltration with ceramic membrane

The car wash wastewater was filtered with ceramic ultrafiltration membrane after pre-treatment

with coagulation and sand filtration. The flux, EC, pH, and turbidity of permeate was recorded

every 10 minutes interval during the period of filtration. The change in flux with time is shown

in Figure 3.10, and it is observed that the initial flux was very high (168 L/m2h) but it dropped

to 60 L/m2h within the next 10 minutes. Then the flux varied between 85 and 125 L/m2h for

the last 60 minutes of filtration. So, the average flux of ceramic membrane was found to be 100

L/m2h.

Figure 3-10 Change in flux with time during ceramic membrane filtration

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

The change of EC and pH of permeate with time was shown in Figure 3.11 and 3.12,

respectively. It was observed in Figure 3.11 that changes of EC with time were showing a

pattern: increasing from 273 to 293 μS/cm then dropped to 278 μS/cm and again increased up

to 298 μS/cm. However, it was found in Figure 3.12 that the pH of permeate was showing an

increasing trend with time.

Figure 3-11 Change of permeate EC with time during ceramic ultrafiltration membrane treatment

It was observed that the initial permeate turbidity was very high (1.84 NTU) but it decreased

with time, and the observed lowest turbidity was 0.86 NTU (Figure 3.13).

Figure 3-12 Change in permeate pH with time during ceramic ultrafiltration membrane treatment

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Figure 3-13 Change in permeate turbidity with time during ceramic ultrafiltration membrane treatment

Relationship between EC of permeate with flux

A relationship is observed between EC of permeate and flux during ceramic ultrafiltration

membrane test as shown in Figure 3.14. When the EC of permeate increased, the corresponding

flux was decreased. This is may be due to fixed rates of transport of ions from the feed to the

permeate during the experiment. Thus, at higher flux, transported ions were diluted more in the

permeate compare to the low flux.

Figure 3-14 Relationship between flux and EC during ceramic ultrafiltration membrane treatment

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Reverse osmosis

The effluent collected from ceramic ultrafiltration membrane was treated with reverse osmosis

to satisfy the standards of recycled water. The change of flux, pH, EC, and turbidity of permeate

with time during reverse osmosis is shown in Figures 3.15 through to 3.18. It was observed

that the permeate flux was fluctuating with time, but the average flux obtained was 10.4 L/m2h.

However, the change in pH with time was showing a decreasing trend, and the average pH

obtained was 5.32 (Figure 3.16). The change of EC with time didn’t show any pattern, and it

varied between 7.6 to 14.6 μS/cm as shown in Figure 3.17. Initially, the permeate turbidity was

high 0.86 NTU, but it decreased with time, and the observed lowest turbidity was 0.16 NTU

(Figure 3.18).

Figure 3-15 Change in flux with time during reverse osmosis experiment

Figure 3-16 Change in pH with time during reverse osmosis experiment

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Figure 3-17 Change in EC with time during reverse osmosis experiment

Figure 3-18 Change in turbidity with time during reverse osmosis experiment

Changes to water quality parameters along the treatment processes

Change in pH along the treatment process

The pH change after each treatment step is shown in the Figure 3.19. The pH of the raw car

wash wastewater was 6.42, but after coagulation, it became 4.47. The reason becoming acidic

is that the FeCl3 react with carbonate and precipitate the Fe(OH)3. So, with the increase of H+

concentration in the solution, the effluent became acidic. According to Stephenson and Duff

(1996), the influence of pH on chemical coagulation/flocculation may be considered as a

balance of two competitive forces such as (1) between H+ and metal hydrolysis products for

interaction with organic ligands and (2) between hydroxide ions and organic anions for

interaction with metal hydrolysis products (Mohamed et al., 2014, Stephenson and Duff, 1996).

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

During sand filtration, H+ was adsorbed by the sand particles and increased the pH. Ceramic

ultrafiltration membrane did not significantly change the pH of the permeate. However, after

treating with the reverse osmosis, permeate became acidic because reverse osmosis can reject

dissolved ions but not dissolved gasses. So, the CO2 present in permeate and feed of reverse

osmosis will be the same amount, and it can react and produce more H+ (APEC water, n.d).

Figure 3-19 Change in pH of the effluent emerging from each treatment process of the Treatment System 1

Change in EC and TDS along the treatment process

The change in EC and TDS after each treatment process showed similar patterns as shown in

Figure 3.20 and 3.21. It was observed that after coagulation, the EC and TDS concentration of

the supernatant were higher compared to the raw car wash wastewater.

Figure 3-20 Change in EC of the effluent emerging from each treatment process of the Treatment System 1

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

However, EC and TDS were reduced by 32% and 42.5%, respectively, after treating with sand

filtration. Ceramic ultrafiltration didn’t show any remarkable effect in reducing the TDS and

EC. But 98% of EC and TDS was removed after treating with reverse osmosis as reverse

osmosis can remove ions. A linear relationship was observed between TDS and EC during this

wastewater treatment as shown in Figure 3.22.

EC= 0.6401 TDS ------------------------------------------------------------------------------------ (3.6)

Where, EC=μS/cm and TDS=mg/L

Figure 3-21 Change in TDS of the effluent emerging from each treatment process of the Treatment System 1

Figure 3-22 Relationship between EC and TDS of the effluents along the treatment processes

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Change in turbidity and suspended solids along the treatment process

Detergents, shampoo and diesel, and suspended solids are the primary reason for making the

car wash wastewater very turbid. The change in turbidity along the treatment process is shown

in Figure 3.23. It was observed that 99% turbidity from car wash wastewater was removed after

coagulation. And it further decreased after sand filtration as most of the remaining suspended

solids were removed. After treating with ceramic ultrafiltration membrane, the observed lowest

turbidity was 0.857 NTU. The final effluent quality from the reverse osmosis membrane was

very high, and the overall turbidity removal by the Treatment System 1 was around 99.94%.

Figure 3-23 Change in turbidity of the effluent emerging from each treatment process of the Treatment System 1

The reduction of suspended solids from car wash wastewater was very high as after coagulation

and sand filtration treatment, 92 and 96% suspended solids were removed respectively as

Figure 3-24 Change in suspended solids of the effluent emerging from each treatment process of the Treatment System 1

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

shown in Figure 3.24. After treating with ceramic ultrafiltration membrane and reverse osmosis,

the removal percentage of suspended solids from car wash wastewater was almost 100%.

Change in COD along the treatment process

Car wash wastewater contains different types of chemical substances from detergents, oils, and

grease, tyres. Thus, the parameter COD needed to be analyzed as it must be reduced to reuse

the treated car wash wastewater. From the Figure 3.25, it is observed that the COD of raw car

wash wastewater was 295 mg/L, but after coagulation, it reduced to 105.5 mg/L with a

reduction percentage of 64%. Sand filtration and ceramic membrane could not be able to reduce

any significant COD. But after treating with reverse osmosis, 96% COD was removed.

Figure 3-25 Change in the average concentration of COD in the effluent emerging from each treatment process of the Treatment System 1

Change in total phosphorus along the treatment process

Eutrophication is one of the major problems if wastewater is discharged into lakes and streams

without any treatment. The usual way to reduce the adverse effect on the environment is by

removing phosphorus from sewage effluents. The concentration of total phosphorus in the

collected raw car wash wastewater was very low (0.32 mg/L). After treatment with FeCl3

coagulant, 100% phosphorus was removed. The primary reaction involved in the precipitation

of phosphorus with iron is as follows.

3−n → FePO4 + nH+

Fe3+ + Hn PO4

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Figure 3-26 Change in the average concentration of total phosphorus in the effluent emerging from each treatment process of the Treatment System 1

Change in total nitrogen, ammonia, nitrate, and nitrite along the treatment

process

- N) to eutrophication of water bodies is very high

The contribution of nitrate-nitrogen (NO3

(Aslan and Cakici, 2007) so it is required to remove it from the effluent before discharge or

reuse. The car wash wastewater treated with coagulation, slow sand filtration, and reverse

osmosis showed an excellent performance in removing nitrate-nitrogen. A considerable

reduction (81%) of ammonia was observed after coagulation as shown in Figure 3.27. The

concentration of nitrite and nitrate of raw car wash wastewater wasn’t available so the removal

efficiency of nitrate and nitrite from coagulation treatment could not be determined. However,

the removal pattern of nitrate and nitrite after treating with sand filtration and membrane during

this treatment process is provided in Figures 3.28 and 3.29. Nakhla and Farooq (2003) observed

that filtration loading rate, filter depth, and grain size during sand filter has a direct impact on

the removal efficiency of total nitrogen. In this experiment, fine sand was used with the

- N) was removed

uniformity coefficient 1.33, and it was observed that 50% of nitrate (NO3

which showed a similar result mentioned by Nakhla and Farooq (2003). A similar pattern was

-) (Figure 3.29). However, after the treatment with ceramic membrane

seen for nitrite (NO2

ultrafiltration and reverse osmosis, nitrate and nitrite were completely removed as suggested

by the literature (Aslan and Cakici, 2007) as shown in Figure 3.28 and 3.29. The removal

efficiency of total nitrogen after each treatment sequence is provided in Figure 3.30. It was

observed that a considerable reduction (50%) of total nitrogen was observed after coagulation

treatment and overall 75% total nitrogen was removed after treating with reverse osmosis.

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Figure 3-27 Change in the average concentration of ammonia in the effluent emerging from each treatment process of the Treatment System 1

Figure 3-28 Change in the average concentration of nitrate in the effluent emerging from each treatment process of the Treatment System 1

Figure 3-29 Change in the average concentration of nitrite in the effluent emerging from each treatment process of the Treatment System 1

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Figure 3-30 Change in the average concentration of total nitrogen in the effluent emerging from each treatment process of the Treatment System 1

Change in heavy metals (copper and zinc) along the treatment process

In this study, the initial concentration of copper and zinc in car wash wastewater was 1.2 and

0.53 mg/L, respectively. After coagulation, the concentration became 0.89 and 0.14 mg/L, as

shown in Figure 3.31 and 3.32 respectively. According to Metcalf and Eddy (2003) when the

removal of the phosphorus in wastewater is accomplished by adding the coagulant at the same

time some other inorganic ions, principally some of the heavy metals are also removed by

precipitation. But the sand filtration and ceramic ultrafiltration membrane did not affect much

on the removal of heavy metal. However, after passing the pre-treated car wash wastewater

through reverse osmosis, the copper and zinc were removed completely as shown in Figure

3.31 and 3.32.

Figure 3-31 Change in the average concentration of copper in the effluent emerging from each treatment process of the Treatment System 1

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Figure 3-32 Change in the average concentration of zinc in the effluent emerging from each treatment process of the Treatment System 1

Particle Size Distribution

According to an International Car wash Association report (2000), the treated water for the

reuse in car wash centers should not contain particles that are larger than 10 μm since these

particles can abrade the skin of the cars when the water is sprayed with high-pressure pumps

(Brown C, 2000). The particle size of the wastewater was determined using laser light

scattering with a Malvern Mastersizer 3000. In the raw car wash wastewater, the particle size

was normally distributed at around 11.4 µm (50% of particles), with lower and upper values of

2.4 and 50 µm, respectively (and a small proportion up to 144 μm). However, after completion

of the treatment sequences, 100% removal of those particles was obtained, as shown in Table

3.6.

Table 3-6 Changes of particle after treatment

Car wash wastewater Coagulation+ Sand Filtration+ UF (0.02 µm) + RO

Dv (10) (μm) 5.18 0

Dv (50) (μm) 11.4 0

Dv (90) (μm) 30.1 0

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Waste generation

Waste generation is one of the difficulties associated with chemical treatment as well as

membrane treatment as the waste generated needs a safe disposal. Four waste streams arose

from the treatment system considered in this chapter.

Waste generation from coagulation

Most chemical precipitations produce sludge. According to Metcalf and Eddy (2003), the

quantity of the sludge can be 0.5% of the volume of treated wastewater if lime is used. In this

study, FeCl3 coagulant was used, and the theoretical value of sludge generated was calculated

by the following equation:

Ms = 86.4 Q (2.9 Fe + SS + M)

Where Ms - mass of dry sludge produced (kg/d)

Q - flow rate of water treated (m3/s)

Fe - iron dose (mg/L of Fe)

SS - suspended solids in raw water (mg/L)

M - other chemicals added (clay, polymer and carbon) (mg/L)

In this study, Qs = 25 L/day; Fe = 15.51 mg/L; SS = 1275 mg/L; M = 0.

Therefore, Ms = 0.033 kg/d

Sludge volume, 𝑉𝑠𝑙= 𝑀𝑠𝑙

𝜌(𝑆𝑠𝑙𝑃𝑠)

Assuming density, ρ = 1000 kg/m3; specific gravity of sludge, Ssl =1.003; sludge solids content,

Ps =1.05%.

Therefore, sludge volume, 𝑉𝑠𝑙 =3.1 L

Thus, the percentage of sludge production was 12.5% after coagulation with FeCl3. So, it can

be said that 12.5% of wastewater became sludge during coagulation with FeCl3 which is higher

than the percentage of sludge which would be generated from the lime.

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Backwash during sand filtration

During sand filtration, periodic back wash was carried out upon the increase in the turbidity

(beyond 1.75 NTU) of the permeate. Approximately 2.5 L tap of water was used for back

washing during sand filtration. So, 10% of wastewater was generated from sand filtration.

Retentate from ceramic ultrafiltration membrane

In the treatment with ceramic ultrafiltration membrane, particles larger than 0.02 μm were

retained in the feed tank. In this study, 4L retentate was generated from 20 L of feed water

during treating with ceramic ultrafiltration membrane. So, the retentate produced is very high

such as 20% of the volume of the feed water. But there was a limitation of the equipment where

a certain amount of water retained inside the pipes of the equipment.

Retentate from reverse osmosis

Reverse osmosis can remove ions, particles, small organic compounds, macromolecules. After

treating with reverse osmosis, 2.8 L retentate was produced from the 10 L of feed. So, 28% of

sludge was generated in this step, which is fairly high. One of the reasons for high percentage

of retentate was the limitation of the equipment. A certain amount of water retained inside the

pipes which cannot be recovered.

Comparison of treated water with the criteria of recycling water and

Standards

According to the Environment Protection Authority (EPA) of Victoria, the quality of recycled

water for the purpose of washing cars should satisfy the criteria required for Class A treated

water. Moreover, there are two different international standards are available for using the

recycling water for washing purpose in car wash centers which are standards in Belgium and

standards in China. After completing the treatment sequence, the characteristics of the treated

water were compared with those standards. Table 3.7 indicates this result in comparison with

EPA Class A recycled water and another two International Standards.

As shown in Table 3.7, coagulation significantly reduced the COD (by 65%) and turbidity (by

99%) of the car wash wastewater, and further removal (small amounts) of these components

by sand filtration. Further elimination of COD or “polishing” of the wastewater by the

ultrafiltration step was also observed. At the end, an overall removal of 96% of the COD from

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

the raw car wash water was achieved by the treatment sequence which meets the EPA of

Victoria and International standards criteria.

Parameter

Coagulation + Sand Filtration

Standard in Belgium

Standard in China

Coagulation (45 mg/L FeCl3)

Car wash waste water

Coagulation + Sand Filtration+ UF (0.02 µm)

Coagulation + Sand Filtration+ UF (0.02 µm) + RO

Recycled water Class A according to EPA

4.47

6.24

6.5

5.32

6-9

6.5-9

6.42

105.5

104.5

88.5

11.5

<125

295

COD (mg/L)

522

2.24

1.49

0.86

0.28

Turbidity (NTU)

100

<60

1275

Suspended solids (mg/L) *NA= Not available

Table 3-7 Comparison of treated water quality with standards

Justification for using ceramic ultrafiltration membrane and reverse

osmosis

Recycling the car wash wastewater is the primary aim of this study, and at the same time,

recycled water quality needs to be high to satisfy the standards required for reuse. FeCl 3

coagulant was very efficient in removing the turbidity and suspended solids from wastewater.

Moreover, a considerable reduction of COD was also achieved from this step. Sand filtration

could able to remove turbidity and COD further. But after these two steps, when the obtained

recycled water quality was compared with standards it could not meet the requirements.

Therefore, further treatment with ceramic ultrafiltration membrane was required. After treating

with ceramic ultrafiltration membrane, car wash wastewater was able to satisfy most of the

criteria except for COD (for the Standards in China). Therefore, further treatment with reverse

osmosis was carried out to meet the COD criteria. However, it generated an enormous amount

of concentrate which needs safe disposal.

Conclusions

The treatment process consists of coagulation, flocculation, sedimentation, sand filtration,

ultrafiltration with ceramic membrane and reverse osmosis were used to produce the car wash

wastewater suitable for recycling according to the standards. The following concluding

statements are prepared considering the findings obtained from this experiment:

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

• The pre-treatment with coagulation-flocculation and sand filtration of the car wash

wastewater before passing through ceramic ultrafiltration membrane and reverse

osmosis were very useful in reducing the fouling of the ultrafiltration and RO

membranes.

• The 45 mg/L FeCl3 coagulant was very efficient in removing the turbidity and

phosphorus from car wash wastewater.

• Ceramic ultrafiltration membrane was very efficient in meeting all the criteria stipulated

for recycling water in Victoria and Belgium but not in China due to COD level.; and

pre-treatment of the car wash wastewater is required before this step. Moreover, it

cannot remove heavy metals completely from the car wash wastewater.

•

In the last stage of the treatment system 1, reverse osmosis was able to satisfy all the

criteria though pre-treatment of the car wash wastewater is required here as well.

• The only concern of this treatment system is the generation of waste (12.5% from

coagulation-flocculation, 10% from sand filtration, 20% from ceramic ultrafiltration

and 28% from reverse osmosis) which requires further treatment and safe disposal.

• The disadvantage of this treatment system is that it is a combination of four different

processes and therefore it increases the difficulty in handling those processes.

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Chapter 4

4 Recycling the car wash wastewater using Enhanced Membrane

Bioreactor (eMBR)

Introduction

Enhanced membrane bioreactor (eMBR) is a relatively new technique for the wastewater

treatment in different industries. However it is becoming popular as it can produce high-quality

effluent. In this research eMBR system was selected as the second treatment system to treat car

wash wastewater for reuse. The experimental setup and operational methodology of the eMBR

treatment system are described in the first section, and the results and data analysis are included

in the second section of this chapter.

Materials and Methods

This section describes setting-up of the experimental system of eMBR, collecting samples from

different car wash centers and developing experimental plan to execute the eMBR operation.

After stabilizing the operation of the eMBR with synthetic wastewater as the influent,

wastewater collected from car wash center was used as influent. The samples were collected

from different locations of eMBR for water quality analysis, and the performance of the

bioreactors and the membrane were monitored. Figure 4.1 illustrates the working steps

involved in this research and those steps are explained in the following sub-sections.

Figure 4-1 Diagram of methodology

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Experimental set-up of Enhanced membrane bioreactor

A laboratory-scale eMBR system was constructed and set-up in the laboratory to conduct

experiments. Initially, eMBR consisted of 2 bioreactors (an anoxic bioreactor (AR1) and an

aerobic membrane bioreactor (AMBR)). But after 28 days another anoxic bioreactor was

included to the system to convert the first anoxic bioreactor to anaerobic bioreactor at later

stages. Recirculation was carried out in the system for first 122 days, and feed was added

manually in each tank. A feed tank and a permeate tank were included to the system after 123

days. The recirculation from AMBR to the first anoxic tank was stopped to make the first

anoxic tank to be an anaerobic tank after 223 days. So, the eMBR system became A2O process

system (A2O processes mean anaerobic, anoxic and oxic treatment processes are combined to

remove nitrogen and phosphorus from the wastewater) consisting of 5 tanks namely feed tank,

anaerobic tank (AR1), anoxic tank (AR2), aerobic membrane bioreactor tank (AMBR) and

permeate tank. The process also included a UV disinfection unit after the AMBR tank. A

schematic diagram shown in Figure 4.2 explains the processes. The reactors were made of

Perspex. The maximum hydraulic capacities for anaerobic, anoxic and aerobic membrane

bioreactor were 4.5, 4.1 and 7.5 L, respectively. A hollow fibre Hydrophilic Polyethersulfone

(H-PES) microfiltration membrane module, supplied by SENUOFIL Co. (pore size 0.1 (μm)

and effective area 0.0127 m2) was submerged in the AMBR under aerobic condition. To

maintain the required level of dissolved oxygen concentration in the bioreactor, the air was

supplied by placing an air diffuser at the base of AMBR tank. This air diffuser also helped to

mix the sludge in the AMBR. The magnetic stirrers were installed underneath the reactors AR1

and AR2 for mixing. To increase the surface area of AR1 and AR2 to encourage the bacterial

growth 65 polypropylene bio-balls (40 mm nominal diameter and 450m2/m3 of specific surface

area which was supplied by ALL Round Aquatics, Australia) were placed in AR1 and AR2.

Recirculation pump was regularly monitored to check the recirculation rate as it was required

to return the nitrified wastewater back to the anoxic tank. The water level in the bioreactor was

controlled by a level sensor which was placed in the AMBR. Peristaltic pumps were used to

feed the eMBR tanks at a uniform feed rate and to pump out permeate (treated effluent) from

the eMBR through the membrane. A vacuum pressure gauge was fitted at the permeate side of

the membrane to measure transmembrane pressure (TMP). Peristaltic pumps were connected

to an electronically controlled timer to operate them intermittently (8 minutes “On” and 2

minutes “Off”). A backward air flow was supplied to the membrane module in the relaxation

period by air regulators and valves to help deal with membrane clogging. It was maintained by

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

adjusting the air flow, and the dissolved oxygen (DO) was kept at 5 mg/L. UV disinfection unit

consists of a UV-C lamp (Wavelength - 254 nm, Total UV dosage - 6.602 Wsec/cm2; power -

20.3 W) and a stainless-steel body, was installed in series with the eMBR.

Figure 4-2 A schematic diagram of the Enhanced Membrane Bioreactor (eMBR)

Influent chemical composition and sample collection

The eMBR was run in the laboratory for 17 months to treat the wastewater collected from

different car wash centers. At first, activated sludge seed was collected from the Anglesea

wastewater reclamation plant to acclimatize with the synthetic wastewater. The composition of

the synthetic wastewater components is shown in Table 4.1. In the subsequent stages of the

experiment, 25%, 50%, 75% and 100% car wash wastewater was added to the synthetic

wastewater, and the eMBR system was run for 27, 26, 27 and 156 days respectively under each

stage.

The car wash wastewater samples were collected from different car wash centers in Melbourne

according to the Standard Method for Examination of Water and Wastewater APHA- 1060

(collection and preservation of samples) and stored in 4 ͦC temperature. Samples brought back

to the room temperature (22±2 ͦC) before using them as feed to the eMBR system as well as

analysing them to obtain water quality data.

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Table 4-1 Components of the synthetic wastewater and their concentrations (Rondon et al., 2015)

Synthetic Wastewater Component

Concentration (mg/L)

Glucose

710

Ammonium Acetate

200

Sodium Hydrogen Carbonate

750

Ammonium Chloride

Potassium Dihydrogen Phosphate

Di-potassium Hydrogen Orthophosphate

Magnesium Sulfate Heptahydrate

Calcium Chloride Dihydrate

Sodium Chloride

Analytical methods

The collected raw car wash wastewater was passed through the eMBR for treatment and

samples from different locations of the eMBR system were collected as indicated in Figure 4.3.

These samples were collected at regular interval and analysed for chemical oxygen demand

(COD), nitrite (NO2

-), nitrate (NO3

-N), ammonia (NH3-N), total Nitrogen (TN), total

phosphorus (TP), pH, dissolved oxygen, electrical conductivity (EC), total dissolved solids

(TDS), oxidation reduction potential (ORP), particle sizes, heavy metals (Pb, Cu, Zn) and

-N were analyzed fortnightly

turbidity. Parameters such as COD, TN, TP, NO2

-, NO3

-N, NH3

and parameters such as pH, DO, EC, TDS, ORP were analyzed twice in a week.

Figure 4-3 Sampling point of the water quality parameter analysis in eMBR systems

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

- were measured by colorimetric techniques using a HACH

COD, TP, TN, NH3-N, NO3

-N, NO2

spectrophotometer (Model DR/4000U) according to the methods 8000, 10127, 10072, 10031,

8039 and 8153, respectively described in HACH protocols. The collected samples from the

eMBR were initially filtered through 0.45 μm filter (mixed cellulose esters) (membrane filter)

(Advantec, Japan). Particle size analyses for the raw car wash wastewater and permeate from

eMBR were carried out using Mastersizer Particle Size Analyser (Malvern Mastersizer 3000)

and turbidity was measured using a turbidity meter (HACH, 2100AN). The pH, DO, EC, TDS

and ORP concentrations of the sample were measured using pH meter (Mettler Toledo), DO

meter (YSI 5100), EC meter (HACH, CDC 401), TDS meter (HACH SENSION MM150) and

ORP meter (ORP-REDOX MTC 101), respectively. Mixed liquor suspended solids (MLSS)

concentration was analyzed according to the Standard Method 2540B. Different types of heavy

metals such as copper (Cu) and zinc (Zn) were found in car wash wastewater. These heavy

metals were determined by using atomic absorption spectroscopy (VARIAN AA240 FS).

E.coli was identified according to AS4276.21-2005: Examination for coliforms and

Escherichia coli-most probable number (MPN) using enzyme hydrolysable substrates

procedure. Oil and grease were determined, and concentration was measured according to the

Standard Method for Examination of Water and Wastewater APHA 5520B ‘Oil and Grease:

Partition-Gravimetric Method’. The concentration of polycyclic aromatic hydrocarbons (PAH)

and polychlorinated biphenyls (PCBs) were determined according to the Standard Method for

Examination of Water and Wastewater APHA 6440C- Gas Chromatograph with mass selective

detector (GC-MS). Moreover, PAH and PCB were measured by Raman Spectrophotometer

(Raman Station 400F). Methylene blue active substances (MBAS) were determined according

to the Standard Method for Examination of Water and Wastewater APHA 5540C ‘Anionic

Surfactants as MBAS’ method.

Experimental Plan

The experimental plan for this research was divided into three different stages depending on

the introduction of the car wash wastewater and the hydraulic retention time (HRT).

First stage: The synthetic wastewater was used to acclimate the microorganisms.

Second stage: The percentage of car wash wastewater was gradually increased in the synthetic

wastewater.

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Final stage: In this stage eMBR was run with 100% car wash wastewater at reduced hydraulic

retention time.

In each stage of the experiment, water quality at five different selected locations of the eMBR

systems was analyzed as shown in Figure 4.3. The changes of the transmembrane pressure and

permeate flux with time were also monitored for the entire period of the experiment.

Short term critical flux

Deposition of particles onto the membrane surface creates membrane fouling, and subsequently,

it increases the transmembrane pressure. A short term critical flux test for the continuous and

intermittent mode of operation of the membrane was conducted to find out the optimum

operating condition required to minimize the fouling of the membrane. Different types of

techniques are available to determine the critical flux: (a) common short term flux step method,

where flux or permeate suction rate is increased by step wise and allowed to stay at a given

step for a fixed duration (less than 1 hour), and the TMP was monitored during this period. (b)

Improved flux step method described by Van der Marel. In this research, common short-term

flux step method was used to assess the fouling.

Common short-term flux step method

The flux of the membrane, J (L/m2s) can be related to the applied transmembrane pressure

ΔTMP (Pa), viscosity of the fluid μ (Pa s) and the membrane resistance R (m-1) according to

Darcy’s Law:

----------------------------------------------------------------------------------------------- (4.1)

J= ΔTMP μR

During the short term critical flux test, the TMP is assumed to change due to fouling. For each

flux step, two TMP values such as the initial TMPi (the first TMP after increasing the flux step)

and final TMPf (at the end of the step) were recorded. A schematic diagram for critical flux

determination is shown in Figure 4.4. From the TMPi and TMPf, the following parameters were

estimated:

𝑛−1------------------------------------------------ (4.2)

Initial TMP increase, ΔTMP0=𝑇𝑀𝑃𝑖

𝑛-𝑇𝑀𝑃𝑓

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

--------------------------------------------------- (4.3)

Rate of increase of TMP, 𝑑𝑇𝑀𝑃 𝑑𝑡

𝑛 𝑛−𝑇𝑀𝑃𝑖 𝑇𝑀𝑃𝑓 𝑛 𝑛−𝑡𝑖 𝑡𝑓

𝑇𝑀𝑃𝑓

----------------------------------------------------------- (4.4)

Average TMP, TMP avg =

𝑛 𝑛+𝑇𝑀𝑃𝑖 2

The flux was estimated by dividing the flow rate (flow rate =volume of collected permeate/

time) by effective membrane area. Flux step durations were taken as 20 and 30 minutes. This

experiment was carried out 12 times in total for six different MLSS conditions (continuous and

intermittent mode) in the AMBR.

Figure 4-4 Schematic diagram of the critical flux determination by the flux-step method

(Le Clech et al., 2003)

Determination the effect of hydraulic retention time (HRT) on permeate

water quality

To treat the wastewater using the eMBR system effectively, the HRT of the eMBR needs to be

reduced. The HRT can be reduced by two ways such as (i) by reducing the volume of reactors

or (ii) by increasing the flow rate of permeate. The flow rate of the permeate can be increased

by increasing the membrane area, by chemical cleaning of the membrane and by running the

eMBR with high TMP. In this experiment, firstly the membrane area was increased, but due to

hydraulic resistance of the membrane, the flow rate didn’t increase. So, in the final stage to

reduce the HRT, membrane was cleaned chemically as well as the volume of the reactors was

reduced and eMBR was run with a high TMP. After that, the permeate quality was checked to

find out the effect of HRT on the permeate quality.

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Cleaning the membrane

Membrane performance was regularly checked by monitoring the transmembrane pressure

(TMP). When TMP reached 40 kPa the membrane was cleaned with deionized water for the

first two stages. When the TMP reaches 40 kPa for the third stage, chemical cleaning was

carried out by immersing the membrane into 12.5% sodium hypochlorite (NaOCl) solution for

50 minutes.

Changes to recirculation rate, flow rate, the speed of magnetic stirrer, DO level in eMBR were

being re-adjusted continuously to ensure the smooth running of the system.

Results and Discussion

Car wash wastewater quality

Car wash wastewater was collected several times from two different car wash centers situated

in Melbourne. First car wash center (car wash center 1) had hand car wash facilities, and the

wastewater samples were collected from the underground tank and the upper tank after grit

removal. The second car wash center (carwash center 2) had an automatic car wash facility,

and four hand carwash facilities and the wastewater samples were collected from the

underground tank. After collecting the samples, wastewater quality was analyzed for various

parameters such as COD, TN, TP, particle size, pH, EC, TDS and their magnitudes are given

in Table 4.2. From Table 4.2, it was observed that the wastewater quality varied with the

location of the car wash center as well as the sample collection point within the same car wash

center. Moreover, the turbidity of wastewater was higher in the summer season (763 NTU in

December 2015) compared to the winter season (289 NTU in August 2016). Tu et al. (2009)

mentioned that in the sunny days the concentration increases with increase in the rate of

evaporation of water. The highest turbidity of collected samples was 763 NTU which falls in

the range from 73-772 NTU mentioned by Lau et al. (2013). The phosphorus and nitrogen

concentration also varied, and the highest nitrogen and phosphorus concentrations found in the

samples were 19.5 and 22.4 mg/L, respectively. The particle size also varied with the collected

location, and the larger size of particles was found from the underground tank compare to the

upper tank. The reason may be the bigger particles were removed by grit removal chamber

located before the upper tank.

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

*NA=Not available

Table 4-2 Raw car wash wastewater quality

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Operational phases of the eMBR

The eMBR was operated in three different stages which were based on the influent

concentration and the HRT. The summary of eMBR operational phases is shown in Table 4.3.

Table 4-3 Operating phases of eMBR

Parameter

Synthetic wastewater

25% Car wash wastewater

50% Car wash wastewater

75% Car wash wastewater

100% Car wash wastewater

After reducing HRT

(Stage1/

(Stage 2/

(Stage 3/

Phase 1)

Phase 2)

Phase 3)

Phase 4)

Phase 5) *

Phase 6)

2.13

2.89

2.04

1.67

1.68

3.08

Influent flow rate (L/d)

0-254

255-281

282-307

308-334

335-463

464-490

(254)

(27)

(26)

(27)

(129)

(27)

Period of operation (day) (number of days)

Feed solution

100% Synthetic wastewater (Concentration shown in Table 4.1)

25% Car wash wastewater +75% Synthetic wastewater (by volume)

50% Car wash wastewater +50% Synthetic wastewater (by volume)

75% Car wash wastewater +25% Synthetic wastewater (by volume)

100% Car wash wastewater (with 1% salts of synthetic wastewater) (by volume)

100% Car wash wastewater (with 1% synthetic salts) (by volume)

Flux (L/m2h)

6.99

9.49

6.69

5.44

5.97

10.13

190

135

184

233

209

Hydraulic retention time, HRT (hr)

No intentional wastage of sludge was made

Solids retention time, SRT (day)

No intentional wastage of sludge was made

3.82

6.16

4.5

3.5

3.1

5.5

Return Activated sludge, RAS (L/d)

64.4:1.75:1

60.5:2.4:1

32.3:1.1:1

95.6:3:1

116:4.9:1

28:0.6:1

Influent COD:TN:TP ratio

*A new membrane module (pore size of 0.1μm and an effective area of 0.0318 m2, hydrophilic Polyethersulfone (H-PES) microfiltration membrane supplied by SENUOFIL Co.) replaced the previous membrane module in the AMBR intermittently for 55 days to reduce the HRT. But due to hydraulic resistance of the new membrane, the flow rate didn’t increase, and as a result, the HRT didn’t reduce during this stage.

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Temporal variation of wastewater quality in eMBR

To check the performance of eMBR, samples were collected from five different locations in

eMBR and were analysed for various parameters. The temporal variations of those parameters

are described in the following sections.

pH

The temporal variations of pH in each reactor are shown in Figure 4.5, and the average value

of each reactor for different phases are given in Table 4.4 and illustrated in Figure 4.6. It was

observed that the average pH in the feed, anaerobic, anoxic, AMBR reactors and permeate were

followed a pattern such as it was decreasing from feed to anaerobic tank then it started to

increase from anoxic to AMBR (Figure 4.5). This same trend was observed in each phase

shown in Figure 4.6. In the AMBR tank the pH should be decreased due to nitrification, but in

this study, it didn’t show that pattern. However, this pattern indicates that the recirculation of

mixed liquor from AMBR to anoxic bioreactor was effective in maintaining the alkalinity.

Moreover, it was observed that after introducing the car wash wastewater the pH value

decreased in each reactor as the pH of the car wash wastewater was acidic and thus with

increasing the proportion of car wash wastewater to the synthetic wastewater in the feed tank,

the pH started to decrease in the feed, anaerobic and AMBR tank (Table 4.4).

Figure 4-5 Temporal variation of pH

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Table 4-4 Average value of pH along the eMBR processes

Operating phase pH

Feed Anaerobic Anoxic AMBR Permeate

Phase 1 7.81 7.01 7.48 8.44 8.65

Phase 2 7.47 6.80 7.26 8.31 7.83

Phase 3 6.89 6.72 7.42 8.29 7.99

Phase 4 6.42 6.48 6.51 7.87 7.60

Phase 5 6.42 6.40 6.88 7.59 7.44

Phase 6 5.76 5.56 6.04 7.31 7.09

Figure 4-6 Change of pH in all reactors during the eMBR processes

Temperature

The temporal variation of the temperature in the feed, AMBR reactors and permeate were

around 20 ͦ C for first four phases but it was higher in phase 5 and 6 after introducing 100% car

wash wastewater. The temperature of anaerobic and anoxic bioreactors was as high as 25 ͦC

and 28 ͦC, respectively, because of the magnetic stirrer underneath the reactor. So, it was

helping to mix the sludge and at the same time raising the temperature of the reactor contents.

A literature survey showed that the nitrification rate increases with the increase in temperature

up to 30 - 35 ͦC. The temporal variations of temperature and the average value of temperature

in different reactors are shown in Figure 4.7 and Table 4.5, respectively.

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Figure 4-7 Temporal variation of temperature

Table 4-5 Average value of temperature along the eMBR processes

Operating phase Temperature (ͦC)

Phase 1

22.1

25.1

19.4

17.3

Phase 2

17.4

17.6

15.1

14.9

Phase 3

13.5

22.9

17.3

16.1

Phase 4

25.4

18.7

Phase 5

23.6

25.3

26.9

26.7

Phase 6

24.8

25.5

28.2

27.8

Feed Anaerobic Anoxic AMBR Permeate

Electrical Conductivity (EC)

The electrical conductivity is the measure of the ability of a solution to conduct an electrical

current. The conductivity increases with the increase in the concentration of ions. The temporal

variation of electrical conductivity is shown in Figure 4.8. From the Figure 4.8, it is observed

that electrical conductivity was increasing initially with time. Initially, there was no membrane

module in the AMBR. So, the dissolved ions were accumulated in the AMBR with time. But

after placing the membrane module on day 123, the dissolved ions started to decrease. The

average value of the electrical conductivity in every reactor is shown in Table 4.6 which shows

a decreasing trend in conductivity from the feed to the permeate which is an indication of the

reduction of dissolved ions from the feed. For example, NH4

+ in the feed is converted to N2 gas

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

due to nitrification followed by denitrification. Also, a trend of decreasing the EC in every

reactor from phase 1 to phase 6 can be observed from Table 4.6 and Figure 4.8.

Figure 4-8 Temporal variation of electrical conductivity

Table 4-6 Average value of EC (μS/cm) along the eMBR processes

Operating phase Electrical Conductivity (μS/cm)

Feed Anaerobic Anoxic AMBR Permeate

Phase 1 1278.7 1206.1 1161.6 1157.1 1211.1

Phase 2 1027.2 1054.8 1030.9 1025.7 1037.3

Phase 3 860.3 838.3 884.1 875.3 951.3

Phase 5 659.6 625.8 682.1 682 704.7

Phase 6 561.3 567.9 552.7 573.8 526

Total Dissolved Solids (TDS)

The temporal variation of TDS in all reactors is shown in Figure 4.9. The TDS showed a similar

trend like electrical conductivity by increasing TDS in AMBR in first few months. But after

placing the membrane module in the AMBR, the TDS started to decrease. The average values

of TDS for first three phases are expressed in Table 4.7 as the TDS meter wasn’t available to

measure during the other phases.

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Figure 4-9 Temporal variation of Total Dissolved solids

Table 4-7 Average value of Total Dissolved Solids along the eMBR processes

Operating phase Total Dissolved Solids (mg/L)

Feed Anaerobic Anoxic AMBR Permeate

818.4 772 743.7 756.1 776.7 Phase 1

657.2 675.2 662.1 649.9 664 Phase 2

550.6 536.5 566 555 608.7 Phase 3

Relationship between electrical conductivity (EC) and total dissolved solids

(TDS)

The measured value of EC is used as a surrogate measure of TDS concentration. From the

literature review, it was found that a linear relationship exists between EC and TDS (Metcalf

& Eddy, 2003) as indicated by equation 4.5.

TDS (mg/L) ≅ EC (μmho/cm) × (0.55-0.70) -------------------------------------------------- (4.5)

The average value of TDS and EC of phase 1, 2 and 3 is given in Table 4.8, and the relationship

between them is shown in the Figure 4.10.

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Table 4-8 The average value of TDS and EC for different phases along the eMBR processes

Phase 1 Phase 2 Phase 3

Reactors TDS EC TDS EC TDS EC

(mg/L) (μS/cm) (mg/L) (μS/cm) (mg/L) (μS/cm)

Feed 818.4 1278.7 657.2 1027.2 550.6 860.3

Anaerobic 772 1206.1 675.2 1054.8 536.5 838.3

Anoxic 743.7 1161.6 662.1 1030.9 554.9 884.1

AMBR 756.1 1157.1 649.9 1025.7 555 875.3

Permeate 776.7 1211.1 664 1037.3 608.7 951.3

From the Figure 4.10, it was observed that a good linear relationship exists between TDS and

EC of this wastewater in this system and it falls in the range stated above.

EC (μS/cm) = 1.56 TDS (mg/L)

TDS (mg/L) = 0.64 EC (μS/cm

Figure 4-10 Relationship between TDS and EC along the eMBR processes

Dissolved Oxygen (DO)

Dissolved oxygen is an important factor in the eMBR system as oxygen is required to maintain

the aerobic condition in AMBR tank. The average value of DO in feed, anaerobic, anoxic,

AMBR and permeate were 4.11, 0.01, 0.13, 8.38 and 8.17 mg/L, respectively, after introducing

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

100% car wash wastewater as feed (Table 4.9). These values confirm that the anaerobic, anoxic

and aerobic conditions had been maintained in respective reactors. The temporal variation of

DO is shown in Figure 4.11.

Figure 4-11 Temporal variation of dissolved oxygen

Table 4-9 Average value of dissolved oxygen along the eMBR processes

Dissolved oxygen (mg/L)

Operating phase

Feed

Anaerobic Anoxic

AMBR

Permeate

Phase 1

8.3

0.27

0.22

7.45

8.23

Phase 2

1.44

0.05

0.15

8.95

8.86

Phase 3

3.06

0.07

0.17

9.4

8.16

Phase 4

2.79

0.04

0.14

8.92

6.74

Phase 5

4.11

0.01

0.13

8.38

8.17

Phase 6

5.98

0.03

0.11

8.18

7.91

Oxidation-Reduction Potential (ORP)

Oxidation Reduction Potential is the activity or strength of oxidizers and reducers in relation

to their concentrations. From Figure 4.12, it is observed that the feed (in some phases), AMBR

liquor and permeate are containing oxidizing agents and feed (in some phases), anaerobic and

anoxic liquors are containing reducing agents. The average value of ORP along the eMBR

process is given in Table 4.10. Appropriate ORP values have to be present in each biological

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

reactor for the removal of nutrients. For example, nitrification is performed in the AMBR by

nitrifying bacteria when the ORP of the wastewater is +100 to +350 mV. From Table 4.10, it

can be seen that the ORP in the AMBR was not always in the ideal range for nitrification to

occur. Thus, care should be taken to maintain proper ORP for nitrification to occur. However,

better conditions for nitrification were observed in phase 5, during which the average ORP in

the AMBR was 100.9 mV. Similarly, denitrification is performed by denitrifying bacteria in

the anoxic tank with ORP of the wastewater is +50 to -50 mV.

Figure 4-12 Temporal variation of ORP

Table 4-10 Average value of ORP (mV) along the eMBR processes

Operating phase ORP (mV)

Feed Anaerobic Anoxic AMBR Permeate

Phase 1 31.1 -323.75 -301.3 44.3 97.9

Phase 2 -523.4 -465.9 -410.8 199 214.1

Phase 3 -68.6 -259.8 -236.5 76.5 136.76

Phase 4 -220 -229.5 -192.8 72.7 83.3

Phase 5 -106.5 -212.86 -229.09 100.9 122.3

Again, in this study, the ORP of the anoxic tank was well below -50 mV which will not support

effective denitrification. Biological phosphorus removal consists of two treatment steps: in the

first step, biological phosphorus release occurs in the anaerobic tank (at ORP range of -100 to

Phase 6 -48.6 -179.2 -223.3 33.6 44.1

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

-225 mV) and in the second step, biological phosphorus removal occurs in the AMBR (at ORP

range of +25 to +250 mV). The eMBR system used in this study had ideal ORP conditions in

both the anaerobic tank (in phases 4, 5 and 6) and the AMBR (in all phases) for the phosphorus

removal to take place.

Relationship between dissolved oxygen (DO) and oxidation-reduction potential

(ORP)

Oxidation-reduction potential is an indication degree for the substance to show the capability

of reducing or oxidizing to another substance. ORP has a relationship with DO such as when

DO declines at the same time ORP decreases (Metcalf & Eddy, 2003). The average value of

DO and ORP for different phases in the eMBR system is shown in the Table 4.11. A quadratic

relationship was observed between DO and ORP for the wastewater used in this eMBR system

from Figure 4.13. Moreover, it was observed that ORP decreased with the decreasing of DO

(Figure 4.13).

Table 4-11 The average value of DO and ORP of different phases in eMBR system

Phase 1 Phase 2 Phase 3 Phase 4 Phase 5

Reactors DO (mg/L) ORP (mV) DO (mg/L) ORP (mV) DO (mg/L) ORP (mV) DO (mg/L) ORP (mV) DO (mg/L) ORP (mV)

Feed Anaerobic Anoxic AMBR Permeate 8.3 0.27 0.22 7.45 8.23 31.1 -323.8 -301.3 44.3 97.9 1.44 0.05 0.15 8.95 8.86 -523.4 -465.9 -410.8 199 214.1 3.06 0.07 0.17 9.4 8.16 -68.6 -259.8 -236.5 76.5 136.76 2.79 0.04 0.14 8.92 6.74 -220 -229.5 -192.8 72.7 83.3 4.11 0.01 0.13 8.38 8.17 -106.5 -212.86 -229.09 100.9 122.3

Figure 4-13 Relationship between dissolved oxygen and oxidation-reduction potential

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Temporal variation of Flux and TMP

The temporal variation of permeate flux and transmembrane pressure of the membrane

submerged in the AMBR are shown in Figure 4.14 and 4.15, respectively. A summary of flux

and TMP along this eMBR system is given in the Table 4.12. In the first phase of the

experiment, the flux was comparatively high (7 L/m2.h), but it decreased with time due to

fouling (Figure 4.14). At the same time, the transmembrane pressure was increased (Figure

4.15). But when TMP reached up to 40 kPa, membrane module was cleaned with deionized

water for the first five phases, so TMP was suddenly decreased (Figure 4.15). After introducing

25% car wash wastewater with synthetic wastewater during phase 2, it was observed that the

average flux was 9.5 L/m2h at a TMP 32 kPa due to low MLSS in the AMBR, but it decreased

to 5.4 L/m2h at a TMP 35 kPa in phase 4 due to fouling. But at the final stage when the

hydraulic retention time of the eMBR system was reduced, the flux increased up to 10.35

L/m2h at a TMP 50.8 kPa.

Figure 4-14 Temporal variation of flux through the membrane submerged in the AMBR

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Figure 4-15 Temporal variation of TMP through the membrane submerged in the AMBR

Table 4-12 Average value of Flux and TMP along the eMBR processes

Operating phase Flux (L/ m2h) TMP (kPa)

Phase 1 7 33.9

Phase 2 9.5 32

Phase 3 6.7 35.4

Phase 4 5.4 35

Phase 5 5.9 35.7

Phase 6 10.13 50.8

Temporal variation of turbidity of permeate

The turbidity of permeate was regularly monitored and it varied between 0.17 to 0.40 NTU

during first five phases, as shown in the Figure 4.16. But, HRT of the system was reduced by

decreasing the volume of the reactors (anaerobic, anoxic and AMBR) and increasing the flux

by chemically cleaning of the membrane in phase 6. After reducing the HRT of the system, it

was observed that the permeate turbidity was started to increase such as 0.83 NTU (on average)

compare to first five phases. But after few days it began to decrease again such as 0.49 NTU

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

(on average). An increasing trend line was observed during first 5 phases but the opposite trend

line was observed in the last phase when the system started to become stable.

Figure 4-16 Temporal variation of turbidity of the permeate

Effect of Flux on Transmembrane Pressure (TMP) and the Turbidity of the

permeate

There is a trend between transmembrane pressure (TMP), and flux was observed in this

research. The TMP increased with the increase in the flux (Figure 4.17). When the flux was

higher, the fouling of the membrane increased, and as a result, TMP was increased. Further,

with the increase in the flux, the permeate water quality deteriorated in terms of turbidity.

Figure 4.18 shows the increase in permeate turbidity with the increase in flux. Moreover, it was

observed from Figure 4.17 and 4.18 that there is a sharp increase in TMP and turbidity when

the flux exceeds 10 L/m2h.

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Figure 4-17 Change of TMP with flux

Figure 4-18 Change of permeate turbidity with flux

Changes to Mixed Liquor Suspended Solids (MLSS) in reactors with time

Initially, synthetic wastewater was used in the feed tank to acclimatize the microorganisms. In

the second stage, different percentages of car wash wastewater were introduced with the

synthetic wastewater. The MLSS was regularly monitored in those stages and found that the

MLSS was decreasing in first 10 days in all the reactors, after changing the influent

concentration. But after a while such as the 16th and 23rd days after changing the influent

concentration, the MLSS was higher compare to the 10th day. The microorganisms required

time to acclimatize with the new influent concentration. Moreover, the MLSS of AMBR was

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

decreasing in those stages because of the lack of food (It was assumed that most of the food

was consumed in the anaerobic and anoxic tanks. So, the microorganisms in the AMBR tank

couldn’t get enough food to grow). The changes of MLSS with time in anaerobic, anoxic and

AMBR liquors after changing the influent concentration is shown in the Figure 4.19.

Figure 4-19 Temporal variation of MLSS in Anaerobic, Anoxic and AMBR tank

COD: TN:TP ratio of all reactors

The general elemental cell composition of microorganisms present in the biological reactors of

the eMBR is C5H7NO2 (Metcalf & Eddy, 2003). Microorganisms require food to generate

energy as well as to synthesise cells. The organic and inorganic compounds of wastewater used

as food by the microorganisms; different compounds donate and accept electrons during

chemical reactions that support the growth and maintenance of microbial cells. The COD: TN:

TP ratio was regularly monitored in the feed, anaerobic, anoxic and AMBR reactors and is

shown in the Figures 4.20 through 4.23. It was found that average COD:TN:TP ratio in the

feed and the anaerobic tank was 77.6:2.8:1 and 39.3:2.5:1, respectively, and it is in the range

between maximum and minimum ratio found in different MBR systems used for wastewater

treatment (Table 2.11). But COD: TN:TP ratio in the anoxic and AMBR was 11.5:1:1 and

6.4:0.8:1, respectively, which was low compare to the other ratios mentioned in Table 2.11.

Because phosphorus wasn’t removed from eMBR system initially. To remove phosphorus first

anoxic tank of the eMBR system was converted as an anaerobic tank. But the phosphorus

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

content wastewater of anoxic and AMBR couldn’t recycle to the anaerobic tank. So,

phosphorus wasn’t removed sufficiently. As a result, the concentration of phosphorus

increased in the anoxic tank and AMBR and therefore the ratio of COD: TN:TP became low.

Figure 4-20 Average COD: TN:TP in the mixed liquor of the feed tank

Figure 4-21 Average COD: TN:TP in the mixed liquor of the anaerobic tank

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Figure 4-22 Average COD: TN:TP in the mixed liquor of the anoxic tank

Figure 4-23 Average COD: TN:TP in the mixed liquor of the AMBR tank

Removal of Organic Compounds

The COD in all reactors and removal percentage of COD during the experimental periods are

presented in Figure 4.24, and it was found that during the first stage the influent COD was very

high (944 mg/L) and the anaerobic reactor could remove 88% of the influent COD. The whole

treatment sequence could remove 98.9% of COD during the first stage. But after the

introduction of the car wash wastewater during the second stage, the COD removal percentage

in the anaerobic and anoxic tank was reduced to 7.24% and 41%, respectively, (on day 333)

due to low MLSS in those reactors. But the whole treatment system could reduce 94% of COD.

In the final stage when microorganisms were at the stable condition the eMBR could reduce

100% of COD. The average value of COD along the eMBR process is given in Table 4.13.

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Figure 4-24 Temporal variation of COD in all reactors as well as removal efficiencies

Table 4-13 Average value of COD (mg/L) along the eMBR processes

Feed Anaerobic Anoxic AMBR Permeate Operating phase

Phase 1 944 225 95 20 10.2

Phase 2 768.8 201.7 94.8 53.3 7.2

Phase 3 437 112 75 51 5.5

Phase 4 473 183 121.5 63 6.3

Phase 5 277.3 189.8 113.8 58 0.5

Phase 6 470 276.5 200 64.5 3

Nitrogen removal

The nitrogen removal depends on some key design parameters such as solids retention time,

temperature, dissolved oxygen (DO), alkalinity, pH and availability of biodegradable COD. It

is occurred in two steps namely nitrification (in the AMBR tank) and denitrification (in the

anoxic tank). In this treatment system, the anoxic tank was placed before the aerobic tank to

increase the availability of electron donor (organic substances) for denitrification. The DO

concentration was maintained very low at around 0.13 mg/L in the anoxic tank, but it was very

high in the aerobic tank (8.38 mg/L) (mentioned in section 4.3.3.6). The solids retention time

was very large as no activated sludge was removed from the system intentionally, so the eMBR

system had sufficient time to allow the growth of Nitrosomonas bacteria to improve

nitrification capability. pH value was maintained at 6.88 and 7.59, respectively, in the anoxic

and AMBR (phase 5) (mentioned in section 4.3.3.1). Recirculation helped to return the nitrified

wastewater to the anoxic tank from AMBR. The average value of the electrical conductivity in

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

every reactor showed a decreasing trend in EC from the feed to the permeate which was an

+ in the feed was

indication of the reduction of dissolved ions from the feed. For example, NH4

converted to N2 gas due to nitrification followed by denitrification.

In the first stage when the feed solution was synthetic wastewater, the highest nitrogen removal

percentage was 85% with a corresponding COD:TN ratio of 70.6. But after introducing the car

wash wastewater, the removal efficiency of nitrogen decreased with decreasing COD:TN ratio.

But it showed a linear relationship where the removal percentage was 66% and 59% with

corresponding COD:TN ratio of 54 and 29, respectively. The change in TN with time and the

percentage of removal are shown in Figure 4.25.

The temporal variation of ammonia (NH3-N), nitrite (NO2-N) and nitrate (NO3-N) are shown

in the Figure 4.26, 4.27 and 4.28, respectively. The overall removal efficiency of ammonia

(NH3-N) from this treatment sequence was very high (93%).

Figure 4-25 Temporal variation of TN in all reactors as well as removal efficiencies

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Figure 4-26 Temporal variations of NH3-N in all reactors as well as the removal efficiencies

Figure 4-27 Temporal variations of NO2-N in all reactors

Figure 4-28 Temporal variations of NO3-N in all reactors

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Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Moreover, it can be seen from Figure 4.27, the concentration of NO2-N in anoxic tank is higher

than the concentration of NO2-N in AMBR. A similar pattern was found for NO3-N. The overall

removal efficiency of NO2-N and NO3-N was 37.5% and 77.9%, respectively. Moreover, the

value of TN, NH3-N, NO2-N and NO3-N on some specific days in different reactors along the

eMBR process is shown in the Table 4.14.

Table 4-14 The value of TN, NH3-N, NO2-N, NO3-N along the eMBR processes

Phase 1 (value on day 206)

Anaerobic

Anoxic

AMBR

Permeate

Parameter

Feed

TN (mg/L)

53.00

35.00

57.50

19.00

21.50

42.6

21.15

19.85

0.4

0.75

NH3-N (mg/L)

0.00

4.75

7.00

1.20

0.00

NO3-N (mg/L)

0.00

1.98

4.26

0.37

0.00

NO2-N (mg/L)

Phase 4 (value on day 333)

Parameter

Feed

Anaerobic

Anoxic

AMBR

Permeate

TN (mg/L)

5.6

1.7

0.6

4.8

0.7

0.6

NH3-N (mg/L)

3.1

2.4

NO3-N (mg/L)

3.7

0.06

0.1

NO2-N (mg/L)

Phase 5 (value on day 398)

Parameter

Feed

Anaerobic

Anoxic

AMBR

Permeate

TN (mg/L)

6.7

4.4

4.5

0.5

NH3-N (mg/L)

5.2

7.6

0.2

6.3

0.2

NO3-N (mg/L)

4.1

1.22

NO2-N (mg/L)

Phosphorus removal

Phosphorus needs to be removed from permeate as it should not be discharged into water

courses due to eutrophication problem. Although there is no standard stipulated for the

allowable concentration of phosphorus in car wash water, this study evaluated the removal of

phosphorus by the eMBR. In this treatment system, the anaerobic tank was introduced in the

eMBR system so that the eMBR could act as a biological nutrient removal (BNR) system. The

key process factors that influence the removal of phosphorus from the feed are (a) anaerobic

zone with the adequate rapidly biodegradable organic matter, (b) subsequent aerobic zone and

In this research, the anaerobic reactor was introduced within the eMBR system after 223 days

of the commencement of the experiment. So, by that time the concentration of phosphorus had

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Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

increased in all reactors. Moreover, there was no recirculation facility available to return the

phosphorus-rich sludge to the anaerobic zone from AMBR. The average value of TP in all

reactors and the temporal variation of TP along the eMBR processes is shown in the Table 4.15

and Figure 4.29, respectively. It was observed in the first and second stages of the experiment

that phosphorus was released in all reactors, but no uptake was observed. In the final stage,

only 7% and 14% phosphorus removal was achieved from this treatment sequence when the

COD:TP ratio was 92 (on day 398) and 30 (on day 481), respectively. However, according to

literature the COD/TP ratio for phosphorus removal should be in the range of 40-50:1 (Water

Environment Federation, 1998) .

Table 4-15 Average value of total phosphorus (mg/L) along the eMBR processes

Operating phase

Phase 1 Feed 14.65 Anaerobic 19.18 Anoxic 19.44 AMBR 19.39 Permeate 19.75

Phase 2 12.70 14.01 20.29 21.73 20.22

Phase 3 13.53 15.11 17.45 20.26 18.64

Phase 4 4.95 6.58 11.81 13.32 15.39

Phase 5 2.39 5.19 5.85 4.85 4.15

Phase 6 16.75 20.11 15.83 14.85 17.34

Figure 4-29 Temporal variation of TP in all reactors

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Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Mass Balance on the eMBR System

In this section, the performance of eMBR in reducing the COD has been discussed for 100%

car wash wastewater as a feed solution with a HRT of 206 hours. A schematic diagram for

mass balance in the eMBR system is shown in the Figure 4.30.

Here, AR1, AR2, and AMBR represents the anaerobic, anoxic and AMBR tanks respectively,

Influent flow rate, Q= 1.8 L/d

Recirculation flow rate, QR= 3.2 L/d

S0, S1, S2, S3 and Se represents the concentration of COD of feed, anaerobic, anoxic, AMBR

and permeates respectively.

X1, X2, and X3 represent the MLSS of the reactors.

COD loading for AR1 (g/Ld) =COD(in)* Flow rate/ volume of reactor

COD loading for AR2(g/Ld) = COD (in)* Flow rate/ volume of reactor +

COD (in from AMBR) * Recirculation rate/ volume of reactor

COD loading for AMBR(g/Ld) = COD(in)*(Flow rate + recirculation rate)/ volume of reactor

COD removal (%) with respect to COD loadings= COD (in) – COD (out)) *100/ COD(feed)

COD removal (%) with respect to influent condition= COD (in) – COD (out)) *100/ COD(in)

Figure 4-30 A schematic diagram for mass balance in the eMBR system

The details calculation for the mass balance are given in the Table 4.16. From the Table 4.16

it was found that the AR1, AR2, and AMBR can remove 40.4, 36.1 and 6.5% COD,

respectively, under these COD loadings conditions. Another 16.5% COD removal was

achieved by the membrane submerged in AMBR. Rondon et al. (2015) have mentioned in their

research that membrane can achieve COD removal as the formation of biofilms on the surface

of the membrane can degrade some organic substances present in the AMBR (Rondon et al.,

2015). In summary, it can be said that the total COD removal achieved from this system is

99.4% with respect to the feed COD concentration at the first phase. But the removal

F/M ratio= COD loading * 1000/MLSS

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Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

percentage of COD in AR1, AR2, and AMBR were 40.4%, 60.5%, and 27.7%, respectively,

with respect to the influent concentration of the reactors and membrane can remove another

97.2% COD. The corresponding food to microorganism ratios of AR1, AR2 and AMBR were

0.18, 0.03 and 0.07 (g-COD/d)/(g-MLSS), respectively. Rondon et al. (2015) found that food

to microorganism ratios in anoxic 1, anoxic 2 and AMBR were 0.54, 0.13 and 0.05 (g-

COD/d)/(g-MLSS), respectively, when treating textile wastewater with eMBR.

Table 4-16 Mass balance on the eMBR system for 100% car wash wastewater (HRT 206 hr)

Anaerobic Anoxic AMBR Membrane

314.5 187.5 74 COD (in) (mg/L) 53.5

187.5 74 53.5 COD (out) (mg/L) 1.5

725 3837 275 MLSS (mg/L)

4.42 4.03 7.19 Volume (L)

58.3 53.1 94.8 HRT (hr)

0.13 0.13 0.052 COD loading (g/Ld)

40.4 36.1 6.5 COD removal (%) (with 16.5

respect to this COD loading)

COD removal (%) (with 40.4 60.5 27.7 97.2

respect to influent condition)

F/M ratio (g COD/g MLSS 0.18 0.03 0.19

day)

COD/TN/TP 23.6:1.13:1 10.15:0.55:1 10.23:0.76:1

Common short term critical flux

Short term critical flux determination tests using common flux step method were carried out

for six different influent conditions (from Phase 1 to Phase 6) based on the ratio of the car wash

wastewater and the synthetic wastewater as well as after reducing the HRT (with 100% car

wash wastewater). These tests were performed for both continuous and intermittent modes.

During intermittent mode, backwash was done to reduce fouling. The flux step duration was

20 minutes for phase 1 test but 30 minutes for all other tests. The flux step was increased by

increasing the flow rate of the suction pump. The critical flux tests for phase 1 to phase 5 were

stopped at a maximum TMP 40 kPa. But for the phase 6, the test started at high pressure such

as 40 kPa and completed at a maximum 62.5 kPa. The conditions of the common short term

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Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

critical flux tests for continuous and intermittent mode are given in the Table 4.17 and 4.18,

respectively.

Table 4-17 Summary of the critical flux tests (continuous mode)

Synthetic wastewater 25% Car wash wastewater 50% Car wash wastewater 75% Car wash wastewater 100% Car wash wastewater After reducing HRT (Phase 1) (Phase 2) (Phase 3) (Phase 4) (Phase 5) (Phase 6)

30 30 30 30 30 20

1.5 1.5 1.5 1.5 1.5 1.5

4.5 7.5 2.3 0.2 18.2 3.6 Step duration (minutes) Flux step height (L/m2h) Starting flux (L/m2h)

Table 4-18 Summary of the critical flux tests (intermittent mode)

Synthetic wastewater 25% Car wash wastewater 50% Car wash wastewater 75% Car wash wastewater 100% Car wash wastewater After reducing HRT (Phase 1) (Phase 2) (Phase 3) (Phase 4) (Phase 5) (Phase 6)

30 30 30 30 30 20

1.5 1.5 1.5 1.5 1.5 1.5

The variations of TMP with time for 3 tests (Phase 1, Phase 4 and Phase 5) during continuous

and intermittent modes of operation are shown in Figures 4.31 and 4.32, respectively. It is

observed in Figure 4.31 that during continuous mode, the TMP (after introducing the car wash

wastewater) reached quickly 40 kPa compared to the time taken in the test with 75% car wash

wastewater. This is because after introducing 100 % car wash wastewater, more fouling

occurred compared to the first stage of experiment which led to less fouling of the membrane.

A similar pattern was found during the intermittent mode of operation which is shown in Figure

4.32. The temporal variations of flux for 3 tests (Phase 1, Phase 4 and Phase 5) were shown for

continuous and intermittent mode in the Figure 4.33 and 4.34, respectively. It was observed

that during this test the flux was fluctuating with time, so no particular trend was observed.

2.3 6.5 4.2 3.7 7.5 8.03 Step duration (minutes) Flux step height (L/m2h) Starting flux (L/m2h)

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Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Figure 4-31 The change of TMP with time (Continuous mode)

Figure 4-32 The change of TMP with time (Intermittent mode)

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Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Figure 4-33 Temporal variation of Flux (Continuous mode)

The membrane performance can be evaluated by monitoring the changes to TMP with flux.

The average flux with average TMP for all the tests for continuous and intermittent mode are

shown in Table 4.19 and 4.20, respectively. It was found that when flux was increased, TMP

increased (Table 4.19). So, it showed an increasing trend between TMP and flux for all tests

(except in phase 5 during continuous mode). However, the increasing trend between TMP and

flux was found for phases 2, 3 and 5 in the intermittent mode. Also, the opposite trend between

TMP and flux was observed for phases 1, 4 and 6 where the flux decreased while the TMP was

increasing beyond 7.5 L/m2h flux due to fouling.

A relation between the fouling rate surrogate term 𝑑(𝑇𝑀𝑃)

with flux was observed for all critical

𝑑𝑇

flux tests during continuous and intermittent mode except for phase 1 test and has been depicted

Figure 4-34 Temporal variation of Flux (Intermittent mode)

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Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

in Table 4.19. It was found that the fouling rate was increasing with the increase in membrane

flux even though a chemical cleaning with 12.5% sodium hypochlorite (NaOCl) was done

before commencing phase 6. From the literature review, it was found that the critical flux was

that point where the dTMP/dt value increases rapidly with flux. It was found that there was no

dTMP/dt was observed during test 1 with synthetic wastewater, but all other tests showed

different trend of fouling rate with Flux. So, in this research, it was decided to take an arbitrary

point such dTMP/dt> 0.2 kPa/min for critical flux (continuous mode). So, the critical flux for

25%, 50%, 75%, 100% and 100% (after reducing the HRT), respectively, car wash wastewater

was 8.41, 11.62, 11.05, 5.15 and 10.28 L/m2h, respectively. However, during intermittent mode,

the point for critical flux was decided where dTMP/dt> 0.25 kPa/min. So, the critical flux for

synthetic wastewater, 25%, 50%, 75%, 100% and 100% (after reducing the HRT), respectively,

car wash wastewater was 7.8, 7.2, 6.5, 4.6, 5 and 7.75 L/m2h, respectively, in intermittent mode.

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Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Table 4-19 Average flux, average TMP, rate of fouling with corresponding flux during critical flux test (continuous mode)

Synthetic (Phase 1) 25% Car wash wastewater (Phase 2) 50% Car wash wastewater (Phase 3) 75% Car wash wastewater (Phase 4) 100% Car wash wastewater (Phase 5) 100% Car wash wastewater (reducing HRT) (Phase 6)

5.22 8.90 9.18 6.62 9.77 10.1 8.55 10.5 10.7 6.45 10.4 11.6 2.3 8.2 6.84 10.98 13.6 13.9 Average Flux (L/m2h)

31 35 40 29 37.7 40 34 38.5 39 27 35 39.1 29.5 37 40 51 58 62 Average TMP (kPa)

0 0 0 0 0.5 0 0 0.25 0 0 0 0.25 0.5 0.25 0 0.5 0.5 0.25 dTMP/dt (kPa/min)

5.22 8.90 9.18 6.62 8.41 10.1 8.55 11.6 10.7 6.45 10.4 11.05 0.54 5.15 6.84 11.08 12.9 10.3 Corresponding Flux (L/m2h)

Table 4-20 Average flux, average TMP, rate of fouling with corresponding flux during critical flux test (intermittent mode)

8.03 8.50 7.79 5.85 8.5 9.3 5.98 8.1 8.37 3.95 7.74 6.3 3.44 4.22 6 7.3 7.94 7.4 Average Flux (L/m2h)

35 37.5 40 29.7 37.5 40 29.6 37.5 38.8 34.5 37 40 22 28.4 40 42.7 49 50.7 Average TMP (kPa)

0 3.13 2.5 0.5 0 0.5 0.25 0 0 2 0 0.5 1.5 0 0.5 1 0.45 1

8.03 8.50 7.80 5.7 8.5 7.2 6.5 8.1 8.37 5.6 7.74 4.6 4.63 4.22 5.01 7.63 7.75 7.27 dTMP/dt (kPa/min) Corresponding Flux (L/m2h)

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Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Moreover, during the critical flux tests, the performance of eMBR was also monitored by checking

the turbidity of permeate. The turbidity of the permeate was less than 0.45 NTU in all tests, but it

showed an increasing trend with the increase in the flux. The change in the permeate turbidity with

membrane flux for both modes are shown in Figure 4.35 and Figure 4.36.

Figure 4-35 Change in the permeate turbidity with membrane flux (continuous mode)

Figure 4-36 Change in the permeate turbidity with membrane flux (intermittent mode)

The critical flux tests were performed under different influent conditions so that the MLSS

concentration in the AMBR was different at each time. After completing all the tests, a relationship

was observed between the membrane flux and the MLSS concentration in the AMBR which is

shown in Figure 4.37. It was found from the Figure 4.37 that the lower the MLSS gives higher

flux as higher MLSS increased the rate of fouling on the membrane. A similar trend between Flux

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Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

and MLSS was described by Yigit et al. (2008) when they carried out critical flux experiments

with five different MLSS concentrations using MBR (Yigit et al., 2008). The following

relationship was observed between MLSS concentration of AMBR and flux.

Y = 78105X-2.855

Here, Y= MLSS of AMBR (mg/L)

X= Flux (L/m2h)

Figure 4-37 Relationship between critical flux and MLSS

Particle size analysis

The International Car Wash Association reported on the range of acceptable particle size that could

be present in the treated water for reuse in car wash centers as bigger particles in the treated water

can damage the surface of a car while performing the wash cycle using a high-pressure pump

(Brown C, 2000). It was mentioned in that report that the particle size of the treated water should

not be greater than 10 μm. The particle size of the collected wastewater was determined using a

Malvern Mastersizer 3000 with laser light scattering. Malvern Mastersizer 3000 can detect the

particles between 0.01 to 3500 µm. These particle size distributions varied in each collected sample.

The particle size for collected sample was distributed around 54.8 µm (50% of particles), with

lower and upper values of 0.523 and 310 µm, respectively, and a small proportion up to 3080 μm.

After treating that wastewater with eMBR system, there was 100% removal of those particles.

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Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Effect of Hydraulic Retention time (HRT) on permeate water quality

Hydraulic retention time (HRT) and solids retention time (SRT) influence the removal efficiency

of organic substances and nutrients. Higher solids retention time helps to keep the higher

concentration of biomass in eMBR. The effect of HRT on the removal efficiency of COD and

styrene content of synthetic wastewater treated by Submerged Bioreactor (SMBR) was

investigated by Fallah et al (2010). They found that the removal efficiency was constantly higher

than 99% and it was not affected by the HRT (Fallah et al., 2010). Moreover, the effect of SRT

and HRT on removal efficiency of COD, ammonia (NH4), phosphate (PO4) for hospital and

residential quarter wastewater was carried out by (Jadhao and Dawande, 2013). In their research,

they found that the removal efficiency reduced with the increase in HRT, but increased with the

increase in the SRT. The effects of HRT on permeate quality, membrane flux and TMP during this

eMBR process is given in Table 4.21. It was observed from the Table 4.21 that COD removal

percentage was very high in all HRT. However, the flux and TMP were increased when the HRT

was reduced.

Table 4-21 Effect of HRT on permeate quality and membrane flux and TMP

HRT (hr)

Flux (L/m2h)

TMP (kPa)

Turbidity (NTU)

COD removal %

TN removal %

94 103 135 184 190 209

10.13 9.21 9.49 6.7 6.99 5.97

50.78 50.25 32 35.4 33.9 35.7

0.83 0.49 0.18 0.26 0.25 0.40

Permeate COD (mg/L) 4.5 1.5 7.25 3.5 10.17 0.5

99.12 99.65 98.94 99.27 98.93 99.84

66.3 54.1 58.9 60 64 63

In this study, the effect of HRT on the removal efficiency of turbidity and COD removal percentage

of permeate was carried out which are shown in Figures 4.38 and 4.39. It was observed from the

Figure 4.38 that the permeate turbidity increased when the HRT was reduced. Moreover, a trend

was observed between permeate turbidity and HRT (Figure 4.38), but there was no specific

relationship between them. But the COD removal percentage was still higher than 98.9% in all

HRT as shown in Figure 4.39. The reason for higher removal rate of COD can be associated with

the stable condition of biomass in the eMBR.

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Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Figure 4-38 Effect of HRT on permeate turbidity

During the long-term experiment conducted in this study, the relationships between the HRT and

flux as well as TMP were observed which are shown in Figure 4.40. It was found that the flux and

TMP were higher for shorter HRT as in the case of 10.13 L/m2.h flux with 51 kPa TMP for 94

hours of HRT. For a flux of 5.9 L/m2.h flux with 35.7 kPa TMP, the HRT was 209 hours. A

relationship between Flux, TMP and permeate turbidity with HRT was observed during this whole

treatment process which is described in the Table 4.22.

Figure 4-39 Effect of HRT on COD Removal percentage

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Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Figure 4-40 Effect of HRT on permeate flux and TMP of membrane

Table 4-22 Relationship between Flux, TMP with HRT along the eMBR processes

Relationship Equations

Flux vs HRT y = -5E-05x2 - 0.018x + 12.103 R² = 0.9467

Here, y= Flux (L/m2h), x=HRT (hours)

TMP vs HRT y = -18.093ln(x) + 130.35 R² = 0.6565

Here, y= TMP (kPa), x=HRT (hours)

Removal of E.coli by the eMBR

Microbial risk is an important factor to be considered when the treated car wash water is considered

for the reuse. Moreover, it is an important parameter for recycling water quality criteria in

Australia. In this study, an ultraviolet disinfection system was used in the eMBR system. The feed

and the permeate samples were analysed for E.coli. The E.coli found in the raw car wash

wastewater was 4900 orgs/100 mL. But after treating the car wash wastewater with eMBR, the

E.coli found in the permeate was 0 orgs/100 mL. The literature review states that other disinfection

systems such as ozonation can remove E.coli, but it could not remove 100% (Etchepare et al.,

2014). But the ultraviolet disinfection system used in this study was able to remove 100% of E.coli.

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Removal of surfactants

Different types of detergents are used for cleaning the cars in the car wash centers and these

detergents contain various types of surfactants. Methylene blue active substances (MBAS)

(anionic) surfactants in the collected car wash wastewater were determined in this research and

found that the concentration was very high such as 83 mg/L compared to 21 mg/L found by Zeneti

et al. (2011). But after treating this wastewater by the eMBR system, the concentration of MBAS

was decreased. The concentration of MBAs was less than <0.05 mg/L in the permeate of eMBR.

So eMBR could remove 99.94% surfactants from the wastewater.

Removal of organic substances by the eMBR

Different types of organic pollutants such as polycyclic aromatic hydrocarbons (PAH) and

polychlorinated biphenyls (PCB) were found in the car wash wastewater with a high concentration

from a study conducted in France (Sablayrolles et al., 2010). So, the collected car wash wastewater

samples were analyzed for those organic compounds by RAMAN spectroscopy and Gas

Chromatography with mass selective detector (GC-MS) method in this research. But no detectable

amounts of PAH and PCB was observed in the wastewater samples.

Removal of Oil and Grease by eMBR

The existence of oil and grease in raw car wash wastewater was identified, and the concentrations

were found to be 25 mg/L which was higher than the 22 mg/L mentioned by Zaneti et al. (2011)

but lower than the 500 mg/L mentioned by Tu et al. (2009). But after treating this wastewater with

the eMBR system, the concentration of oil and grease in the permeate was found to be less than 5

mg/L. So, it can be said that the eMBR was able to remove at least 80% of oil and grease from the

car wash wastewater. Moreover, this permeate quality satisfied the Recycled Water Class A criteria

of EPA Victoria (mentioned in Table 2.5).

SEM Analysis of Membrane

SEM was conducted on the membrane. The inner surface of the new microfiltration (MF)

membrane was shown in Figure 4.41, and the fouled membrane is provided in Figure 4.42.

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Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Figure 4-41 SEM of new membrane (MF)

From the Figure of fouled membrane, it can be observed that the pore was less compare to virgin

membrane and surface was covered with pollutants.

Figure 4-42 SEM of used membrane in MBR

Comparison of permeate water quality with recycle water quality standards

According to the Environment Protection Authority (EPA) of Victoria, the quality of recycled

water for car washing purpose should satisfy the criteria required for Class A water. Moreover, 116

Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

two different international standards are available for using recycling water for washing purpose

in car wash centers (Standards for Belgium and China). The quality of effluent from the eMBR is

compared with those standards, and it was found that the effluent from the eMBR meets all the

water quality criteria require for recycling (Table 4.23).

Table 4-23 Comparison of the quality of the effluent from eMBR with the water quality standards required for recycling

Treated

Recycled water

Standard in

Parameter

water from

Class A according

Belgium

China

eMBR

to EPA

7.38

6-9

6.5-9

1.5

COD (mg/L)

<125

0.28

Turbidity (NTU)

E. coli org/100 mL < 10

<60

Suspended solids

(mg/L)

Comparison of permeate quality between two treatment systems

A comparison was done between two different membrane based treatment systems (treatment

system 1 and eMBR) used in this research for recycling the car wash wastewater regarding the

permeate quality and shown in the Table 4.24. It is observed that the first treatment system was a

combination of four different systems that is coagulation-flocculation-sedimentation, sand

filtration, ceramic ultrafiltration membrane and reverse osmosis and pre-treatment were required

for the wastewater before passing through the membrane system to reduce the fouling. Moreover,

sludge disposal was required after each treatment sequence. Alternatively, eMBR system is a

combination of membrane separation, biological degradation, and UV disinfection and it didn’t

require any pre-treatment. No sludge was required to dispose during this 17 months’ experiment.

Though the permeate quality from both systems was very high to satisfy the standards.

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Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Table 4-24 Comparison of permeate quality between two treatment systems

Coagulation-flocculation, sand filtration, ceramic

Enhanced membrane bioreactor

ultrafiltration membrane and reverse osmosis

(eMBR)

During experiment

Pre-treatment required

No Pre-treatment required

Physicochemical processes

Biological + Physical disinfection

Sludge management required

Sludge wasting is minimum

Permeate quality

Coagulation-flocculation, sand

Enhanced membrane bioreactor

filtration, ceramic ultrafiltration

(eMBR)

membrane and reverse osmosis

Parameter

Feed

Permeate

Removal % Feed

Permeate Removal %

Turbidity (NTU)

522

99.94

569

0.28

99.95

0.28

96.1

429.5

1.5

99.6

COD (mg/L)

295

11.5

74.4

62.5

TN (mg/L)

19.5

52.6

6.7

0.5

92.5

9.5

4.5

NH3-N (mg/L)

CONCLUSIONS

A lab scale eMBR was studied for more than 17 months to treat the car wash wastewater for

recycling purpose. The following conclusions are made based on observation and findings from

this study.

▪

The collected car wash wastewater from different car wash centers was treated with eMBR

to check the robustness of the system.

▪

The permeate water quality was found to be very high, and the turbidity was 0.29 NTU on

average.

▪

The critical flux test results indicated that fouling rate becomes lower in continuous mode

compared to the intermittent mode.

▪

A linear relationship between TMP and flux was observed during critical flux experiment.

▪

The concentration of car wash wastewater influenced the MLSS of all reactors, but the

microorganisms could adjust with the new environment.

▪

From the result of mass balance on the eMBR, it can be said that a similar treatment system

can be established in car wash center to recycle the treated wastewater.

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Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

▪

The COD removal by the eMBR is very high.

▪

Phosphorus removal can be obtained by increasing the ratio of COD/TP and by arranging

a recirculation system from AMBR to anaerobic tank.

▪

The HRT of the eMBR can affect the permeate water quality however the effect can be

reduced after stabilizing the biomass concentrations in all reactors.

▪

It was found that the eMBR was able to reduce 100% E.coli.

▪

The treated permeate quality satisfied all the standards required for recycling.

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Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Chapter 5

5 Conclusions and Recommendations

Conclusions

Water scarcity is a major issue in the world due to the increase in population. Therefore, recycling

the wastewater from all sectors will contribute to solve the water scarcity problem. It was found

that around 35 billion litres of contaminated car wash wastewater is generated from 10,000 car

wash centers in Australia every year and it has an enormous impact on the environment as it

contains various types of pollutants (Boluarte et al., 2016). After critically evaluating the literature

review of various treatment systems previously used by different researchers, two membrane based

treatment systems were selected in this study. The collected car wash wastewater from various car

wash centers was treated by those treatment systems and findings are summarised below.

Treatment system 1: Coagulation-flocculation, sand filtration, ceramic ultrafiltration membrane

and reverse osmosis

The first treatment system was a combination of four different systems that is coagulation-

flocculation-sedimentation, sand filtration, ceramic ultrafiltration membrane and reverse osmosis.

After treating the car wash wastewater with this treatment system, the most important findings are

listed below:

• The pre-treatment with coagulation-flocculation and sand filtration of the car wash

wastewater before passing it through ceramic ultrafiltration membrane and reverse osmosis

was very useful in reducing the fouling of the ultrafiltration and RO membranes.

Figure 5-1 A schematic diagram of treatment system 1

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Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

• The 45 mg/L FeCl3 coagulant was very efficient in removing the turbidity and phosphorus

from car wash wastewater, but 12.5% (by volume) of sludge was generated from this stage.

•

It was found that the permeate from ceramic membrane ultrafiltration met all the criteria

for recycling water, except the COD. However, pre-treatment of the car wash wastewater

was required before this step. Moreover, it cannot remove heavy metals from the car wash

wastewater, and it produced 20% (by volume) of waste in the form of concentrate.

• However, reverse osmosis could satisfy all the criteria though pre-treatment of the car wash

wastewater is required prior to the RO process. Also, 28% (by volume) of sludge was

generated from this stage.

• This treatment system is sufficient to produce high-quality recycled water which can be

reused for washing the cars in a car wash center. But the disadvantage of this treatment

system is that it is a combination of four different processes, and therefore it increases the

difficulty in handling those operations. Also, it produces large quantities of waste which

need further treatment and disposal.

Treatment system 2: Enhanced Membrane Bioreactor (eMBR)

An enhanced membrane bioreactor (eMBR) comprised of one anaerobic bioreactor (AR1), one

anoxic bioreactor (AR2), one aerobic membrane bioreactor (AMBR) and UV physical disinfection

unit was selected as the second treatment system. The treatment system was set-up in the

laboratory and ran for 17 months for treating the car wash wastewater collected from various car

wash centers located in Melbourne. Based on the findings from this treatment system, the most

important conclusions are listed below:

Figure 5-2 A schematic diagram of treatment system 2

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Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

▪ The permeate water quality from eMBR was found to be very high, and the turbidity was

0.28 NTU on average. Also, this treated permeate quality satisfied all the standards

required for recycling the water in car wash centers.

▪ The concentration of car wash wastewater influenced the MLSS of all reactors, but the

microorganisms could adjust to the new environment. When 100% car wash wastewater

was treated by the eMBR, the average MLSS concentration in AR1, AR2, and AMBR were

617, 4400 and 333 mg/L, respectively.

▪ From the mass balance computations on the eMBR, it can be said that a similar treatment

system can be established in car wash center to recycle the treated wastewater.

▪ The HRT of the eMBR can affect the permeate water quality however the effect can be

reduced after stabilizing the biomass concentrations in all reactors.

▪

It was found that the eMBR was able to reduce E.coli by 100%.

▪ The critical flux test results indicated that fouling rate becomes lower in continuous mode

compared to the intermittent mode. The critical flux for 25%, 50%, 75%, 100% and 100%

(after reducing the HRT) car wash wastewater was 8.41, 11.62, 11.05, 5.15 and 10.28

L/m2h, respectively in continuous mode. However, the critical flux for synthetic

wastewater, 25%, 50%, 75%, 100% and 100% (after reducing the HRT) car wash

wastewater was 7.8, 7.2, 6.5, 4.6, 5 and 7.75 L/m2h, respectively in intermittent mode.

▪ The membrane was operated at an average TMP of 32.8 kPa and flux 6.34 L/m2h, but the

rate of increase of TMP was high (50.8 kPa) when the flux was high (10.13 L/m2h) at a

given MLSS (175 mg/L MLSS in AMBR) concentration.

▪ Moreover, during this 17 months of operation no sludge was wasted intentionally from this

system, and therefore the SRT was very high.

▪ This system is easy to maintain as it is a combination of membrane separation, biological

degradation, and UV disinfection.

Based on the above findings and observations it can be concluded that the eMBR was able to

produce high-quality recycled water which is required for the reuse in car wash centers.

However, for further improvements of the eMBR system, some recommendations are stated

below.

Recommendations for future work on eMBR systems

▪ A pilot-scale study on eMBR is required to develop a design for real time operations.

▪ A detailed cost-benefit analysis is required before the commercialization of this system.

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Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

▪ Microorganisms play a vital role in eMBR. Therefore, the characteristics of the

microorganisms treating the car wash wastewater should be investigated in detail.

▪ The foulant of the car wash wastewater should be analysed further to reduce the fouling of

the membrane.

▪ Better membrane modules (with respect to membrane material and module configuration)

are needed to assess the effect of the hydraulic retention time on permeate quality.

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Appendix

128

Appendix: Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Treatment system 1 (Coagulation-Flocculation, Sand filtration, Ceramic Ultrafiltration and Reverse Osmosis)

Experimental data of treatment system 1

Water quality changes after each treatment step

unit Raw Car wash waste water Coag+ Sand Filtration Coagulation (45 mg/L FeCl3) Coag+Sand Filtration.+ Ceramic (0.02 µm) Coag+Sand Filt.+Ceramic (0.02 µm)+RO

°C - µS/cm 18.9 6.42 404 19.25 6.24 363.50 25.16 6.5 306 23.0 5.32 8.99 19.9 4.47 580

temperature pH Electroconductivity Total Dissolved Solids Turbidity mg/L NTU 259 522 232.50 1.49 196 0.86 5.76 0.28 371 2.24

Chemical Oxygen Demand Ammonia Total Phosphorus Total Nitrogen Nitrite Nitrate Suspended Solids Copper (217.9) Zinc (213.9) mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L 295 9.5 0.32 19.5 NA NA 1275 1.2 0.53 104.50 5.70 0.0 9.30 1.22 2.40 50 0.56 0.38 88.5 4.55 0.0 9 0.3 1.7 0.0 0.76 0.26 11.5 0.50 0.0 5.0 0.0 0.0 0.0 0.0 0.01 105.5 1.75 0.0 10.50 1.22 4.8 100 0.89 0.14

• Average value is given for all parameter analysis • NA= Not available

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Appendix: Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Changes of permeate turbidity during sand filtration

Time (min) Turbidity (NTU)

5 10 15 20 2.32 2.37 2.35 2.23

25 30 35 40 45 50 55 60 65 70 75 80 85 90 2.03 1.92 1.83 1.75 1.6 1.59 1.58 1.56 1.53 1.49 1.52 1.53 1.61 1.75

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Appendix: Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Flux, flow rate and changes of permeate quality during ceramic membrane ultrafiltration

pH Time (min) EC (μS/cm) Turbidity (NTU) Flow (L/hr) Flux (L/m2h) Volume collected (mL) Cumulate Collected Volume (mL)

62 168 620 2300 273 276 1.84 7.44 20.16 6.81 6.88 620 1680

60 3500 7.20 1200 1.41

85 5200 10.20 1700 1.4

293 294 291 294 6.9 6.92 7 6.97 90 7000 10.80 1800

112.5 9250 280 278 1.32 13.50 7.06 7.03 2250

125 11750 15.00 2500 0.972

110 13950 2200 13.20

35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 1950 15900 292 294 295 292 298 0.963 0.857 0.989 11.70 7.21 7.11 7.22 7.19 7.24 97.5

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Appendix: Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Flux, flow rate and changes of permeate quality during reverse osmosis

pH Time (min) EC (μS/cm) Turbidity (NTU) Flux (L/m2h) Volume collected (mL) Cumulate Collected Volume (mL) Flow rate (L/h)

0 0 0

11.4 6.32

5.02

10.79

6.32 0.856 0.321 0.396 0.388

5.55

0.388

6.24

5.05 0.197 0.195

4.75 0.158

4.8 0.173

4.95 0.178

4.88 0.196

5.03 0.168

2.10 2.76 3.96 3.84 3.84 3.60 3.96 4.68 2.76 4.56 3.36 4.32 2.76 2.16 3.24 5.04 4.08 3.36 5.40 3.60 4.08 4.44 4.80

4.98 8.32 7.58 7.6 7.83 11.45 9.02 8.23 7.8 9.04 12.65 9.15 14.09 9.98 10.35 10.85 11.83 14.17 14.63 0.245 5.68 7.46 10.70 10.38 10.38 9.73 10.70 12.65 7.46 12.32 9.08 11.68 7.46 5.84 8.76 13.62 11.03 9.08 14.59 9.73 11.03 12.00 12.97 350 580 910 1230 1550 1850 2180 2570 2800 3180 3460 3820 4050 4230 4500 4920 5260 5540 5990 6290 6630 7000 7240 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 118 350 230 330 320 320 300 330 390 230 380 280 360 230 180 270 420 340 280 450 300 340 370 240

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Appendix: Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Sand filtration modelling data and calculation

Effluent concentration at 90 minutes (per mL) (V) Influent concentratio n (per mL) (V0) Radius of particle s (ap) (µm) Effluent concentratio n at 90 minutes (% volume) (V) Nin/N0 at the beginning of filtration * Influent concentratio n (% volume in particles) (V0) Number concentratio n of particles in Influent (N0) (per mL) Nend/N0 after 90 minutes of filtratio n Surface area coverag e during sand filtration Number concentration of particles in effluent (Nend) at 90 minutes (per mL) Number concentratio n of particles in effluent (Nin) at beginning (per mL)

0.878 0.664 0.557 0.510 0.488 0.476 0.470 0.464 0.455 0.445 0.434 0.423 0.413 0.419 0.420 0.416 0.403 0.387 0.361 0.328 0.278 0.875 0.875 0.875 0.875 0.875 0.875 0.875 0.875 0.875 0.875 0.875 0.875 0.875 0.875 0.875 0.875 0.875 0.875 0.875 0.875 0.875 0.0005 0.0013 0.0022 0.0030 0.0038 0.0045 0.0050 0.0053 0.0054 0.0053 0.0050 0.0046 0.0040 0.0033 0.0026 0.0021 0.0016 0.0011 0.0008 0.0006 0.0004 7.64 8.68 9.86 11.2 12.7 14.5 16.4 18.7 21.2 24.1 27.4 31.1 35.3 40.1 45.6 51.8 58.9 66.9 76 86.4 98.1 0.45 0.7 1.06 1.53 2.1 2.76 3.46 4.14 4.75 5.22 5.52 5.62 5.5 5.19 4.73 4.15 3.52 2.87 2.26 1.74 1.35 0.0045 0.007 0.0106 0.0153 0.021 0.0276 0.0346 0.0414 0.0475 0.0522 0.0552 0.0562 0.055 0.0519 0.0473 0.0415 0.0352 0.0287 0.0226 0.0174 0.0135 0.79 0.93 1.18 1.56 2.05 2.63 3.25 3.84 4.32 4.65 4.79 4.75 4.54 4.35 3.97 3.45 2.84 2.22 1.63 1.14 0.75 0.00395 0.00465 0.0059 0.0078 0.01025 0.01315 0.01625 0.0192 0.0216 0.02325 0.02395 0.02375 0.0227 0.02175 0.01985 0.01725 0.0142 0.0111 0.00815 0.0057 0.00375 2410261 2556645 2641233 2601171 2448723 2162403 1873597 1512193 1190742 890740 640942 446259 298655 192250 119151 71317 41146 22895 12297 6444 3416 2115673 1698343 1470120 1326087 1195210 1030275 879941 701307 541474 396738 278090 188588 123263 80567 50003 29644 16599 8855 4435 2111 949 2110115 2238271 2312325 2277252 2143788 1893123 1640281 1323882 1042461 779818 561127 390687 261464 168309 104313 62436 36022 20044 10766 5641 2990

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Appendix: Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

0.218 0.155 0.118 0.088 0.076 0.065 0.058 0.049 0.040 0.022 0.012 0.009 0.031 0.105 0.235 0.386 0.475 0.514 0.532 0.536 0.541 0.542 0.539 0.535 0.530 0.523 0.518 0.875 0.875 0.875 0.875 0.875 0.875 0.875 0.875 0.875 0.875 0.875 0.875 0.875 0.875 0.875 0.875 0.875 0.875 0.875 0.875 0.875 0.875 0.875 0.875 0.875 0.875 0.875 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0002 0.0002 0.0002 0.0001 0.0001 0.0001 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 111 127 144 163 186 211 240 272 310 352 400 454 516 586 666 756 859 976 1110 1260 1430 1630 1850 2100 2390 2710 3080 1.1 1 1.02 1.14 1.31 1.46 1.54 1.53 1.39 1.15 0.86 0.57 0.32 0.19 0.17 0.22 0.4 0.71 1.1 1.51 1.84 2.03 2.04 1.86 1.52 1.07 0.55 0.011 0.01 0.0102 0.0114 0.0131 0.0146 0.0154 0.0153 0.0139 0.0115 0.0086 0.0057 0.0032 0.0019 0.0017 0.0022 0.004 0.0071 0.011 0.0151 0.0184 0.0203 0.0204 0.0186 0.0152 0.0107 0.0055 0.48 0.31 0.24 0.2 0.2 0.19 0.18 0.15 0.11 0.05 0.02 0.01 0.02 0.04 0.08 0.17 0.38 0.73 1.17 1.62 1.99 2.2 2.2 1.99 1.61 1.12 0.57 0.0024 0.00155 0.0012 0.001 0.001 0.00095 0.0009 0.00075 0.00055 0.00025 0.0001 0.00005 0.0001 0.0002 0.0004 0.00085 0.0019 0.00365 0.00585 0.0081 0.00995 0.011 0.011 0.00995 0.00805 0.0056 0.00285 1921 1166 816 629 486 371 266 182 111 63 32 15 6 2 1 1 2 2 2 2 2 1 1 0 0 0 0 419 181 96 55 37 24 16 9 4 1 0 0 0 0 0 0 1 1 1 1 1 1 0 0 0 0 0 1682 1021 714 550 426 325 233 159 98 55 28 13 5 2 1 1 1 2 2 2 1 1 1 0 0 0 0

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Appendix: Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Picture of treatment system 1

Coagulation test (Jar test)

After 30 minutes of settling during jar test

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Appendix: Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Sand filter

Ceramic membrane

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Appendix: Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Reverse Osmosis

Collected car wash wastewater

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Appendix: Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Permeate from Ceramic membrane ultrafiltration

Permeate from Reverse Osmosis

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Appendix: Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Treatment system 2 (Enhanced membrane bioreactor)

Experimental date of Treatment system 2 Average value of pH in all reactors

Date Day Feed Anoxic Tank AMBR Permeate

17/11/2015 18/11/2015 20/11/2015 23/11/2015 25/11/2015 27/11/2015 30/11/2015 2/12/2015 4/12/2015 7/12/2015 9/12/2015 11/12/2015 15/12/2015 20/01/2016 27/01/2016 29/01/2016 1/02/2016 3/02/2016 5/02/2016 10/02/2016 12/02/2016 15/02/2016 17/02/2016 19/02/2016 22/02/2016 25/02/2016 1/03/2016 7/03/2016 12/03/2016 16/03/2016 18/03/2016 24/03/2016 27/03/2016 13/04/2016 15/04/2016 18/04/2016 7 8 10 13 15 17 20 22 24 27 29 31 35 71 78 80 83 85 87 92 94 97 99 101 104 107 112 118 123 127 129 135 138 155 157 160 Anaerobic Tank 7.36 6.85 6.81 5.90 6.46 7.57 7.65 7.77 6.96 7.37 7.07 6.69 6.72 7.40 7.29 7.18 7.20 7.29 7.10 6.95 6.64 7.10 6.96 6.28 7.01 6.83 7.07 7.29 7.34 7.31 6.95 7.16 6.38 6.80 6.85 7.76 7.90 7.84 7.75 7.77 7.74 5.47 7.73 7.96 7.01 8.11 8.53 8.05 8.27 8.25 8.55 8.15 8.25 7.27 8.26 7.58 7.07 7.17 6.68 8.38 7.48 7.53 7.17 7.27 7.41 7.44 5.41 8.27 8.12 6.96 8.00 7.30 7.41 8.11 8.34 8.28 8.21 7.40 7.87 6.89 7.03 7.34 8.28 8.71 8.79 5.96 5.89 8.63 8.51 8.65 8.32 8.54 8.62 8.46 8.70 8.97 8.81 8.41 8.44 8.66 8.70 8.75 8.69 8.75 7.96 8.77 8.67 7.84 9.08 8.64 9.20 9.12 9.10 8.93 8.83 8.83 8.71 8.83 8.93 9.05 8.93 8.91 8.85

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Appendix: Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

162 164 204 209 217 223 230 232 234 237 253 258 261 266 280 286 293 298 302 318 324 332 335 339 358 367 377 405 408 432 446 458 471 482 7.12 8.22 7.88 7.75 7.97 7.80 7.89 7.95 7.80 7.85 7.41 7.37 7.89 7.37 7.25 6.59 7.11 7.05 6.83 6.16 6.47 6.63 6.55 6.48 6.24 6.47 6.03 6.83 6.75 6.42 6.63 5.86 5.67 5.84 7.48 7.40 7.64 7.49 7.61 7.37 7.50 6.82 8.11 8.04 6.78 6.93 6.85 7.90 7.36 7.70 7.47 7.26 7.27 6.93 6.11 6.49 6.93 7.30 7.18 6.81 6.80 6.91 6.90 6.84 6.72 6.45 6.09 5.98 8.12 8.40 7.86 8.33 8.45 8.37 8.57 8.15 8.18 8.08 7.85 8.64 8.62 7.63 8.35 8.52 8.35 8.21 8.09 7.84 7.76 8.01 7.92 7.57 7.79 7.99 7.68 7.52 7.55 7.11 7.48 7.27 7.32 7.29 7.03 6.91 6.89 7.29 7.02 6.76 6.60 7.93 6.98 7.06 6.35 6.98 6.74 6.75 6.73 6.68 6.65 6.70 6.85 6.42 6.80 6.21 6.48 6.65 6.28 6.33 6.26 6.30 6.66 6.57 6.68 5.77 5.58 5.53 8.69 8.85 8.24 8.49 8.73 8.61 8.64 8.69 8.43 8.25 7.96 8.45 7.51 7.35 8.03 8.09 7.99 8.02 7.85 7.70 7.60 7.51 7.79 7.52 7.72 7.60 7.45 7.18 7.45 7.36 7.25 7.13 7.13 7.05 20/04/2016 22/04/2016 1/06/2016 6/06/2016 14/06/2016 20/06/2016 27/06/2016 29/06/2016 1/07/2016 4/07/2016 20/07/2016 25/07/2016 28/07/2016 2/08/2016 16/08/2016 22/08/2016 29/08/2016 31/08/2016 7/09/2016 23/09/2016 29/09/2016 7/10/2016 10/10/2016 14/10/2016 2/11/2016 11/11/2016 21/11/2016 19/12/2016 22/12/2016 15/01/2017 29/01/2017 10/02/2017 23/02/2017 6/03/2017

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Appendix: Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Average value of EC (μS/cm) in all reactors

Feed Anaerobic Tank AMBR Permeate Anoxic Tank

7 8 9 10 13 15 17 20 22 24 27 29 31 35 71 73 76 78 80 83 85 87 92 94 97 99 101 104 107 112 118 123 127 129 135 138 155 157 160 162 981.50 1019.00 955.00 1000.00 1106.67 1094.33 904.00 1046.33 1245.33 1230.33 1337.00 1097.00 1452.33 1681.33 1717.00 1447.33 1392.67 1143.00 1577.33 1447.33 1414.33 1397.00 1373.67 1347.67 1332.50 1307.67 1344.00 1342.67 1296.00 1276.33 1187.67 1176.67 1191.67 1198.33 1173.67 1310.00 1220.00 1208.50 887.00 957.00 962.50 938.50 957.33 966.00 952.33 992.67 834.67 857.00 1332.33 1278.33 1171.00 1226.00 1184.33 1267.00 1441.00 1551.33 1443.33 1344.67 1307.33 1422.67 1174.33 1212.00 1277.00 1279.00 1319.50 1299.50 1307.50 999.00 927.00 960.00 1015.00 980.00 846.67 956.00 957.33 842.33 697.00 1187.00 1236.33 1227.67 1149.67 1168.33 1333.33 1461.67 1384.67 1341.67 1327.67 1315.67 1261.33 1291.67 1275.00 1300.33 1292.67 1305.33 1275.00 1270.00 1287.67 1270.67 1262.67 1196.33 1152.67 1198.00 1108.67 1126.67 1126.50 1199.50 1215.50 1010.00 907.00 1015.00 1006.00 1013.67 964.33 826.33 968.67 829.33 821.33 1207.67 1217.00 1211.33 1195.33 1165.67 1315.67 1341.00 1377.33 1392.33 1355.33 1264.67 1314.00 1281.00 1250.67 1236.67 1120.33 1318.00 1268.33 1329.00 1355.33 1283.33 1235.33 1236.33 17/11/2015 18/11/2015 19/11/2015 20/11/2015 23/11/2015 25/11/2015 27/11/2015 30/11/2015 2/12/2015 4/12/2015 7/12/2015 9/12/2015 11/12/2015 15/12/2015 20/01/2016 22/01/2016 25/01/2016 27/01/2016 29/01/2016 1/02/2016 3/02/2016 5/02/2016 10/02/2016 12/02/2016 15/02/2016 17/02/2016 19/02/2016 22/02/2016 25/02/2016 1/03/2016 7/03/2016 12/03/2016 16/03/2016 18/03/2016 24/03/2016 27/03/2016 13/04/2016 15/04/2016 18/04/2016 20/04/2016

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Appendix: Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

22/04/2016 1/06/2016 6/06/2016 14/06/2016 20/06/2016 27/06/2016 29/06/2016 1/07/2016 4/07/2016 20/07/2016 25/07/2016 28/07/2016 2/08/2016 16/08/2016 22/08/2016 26/08/2016 29/08/2016 31/08/2016 10/10/2016 14/10/2016 2/11/2016 11/11/2016 21/11/2016 22/12/2016 15/01/2017 29/01/2017 10/02/2017 23/02/2017 6/03/2017 164 204 209 217 223 230 232 234 237 253 258 261 266 280 286 290 293 295 335 339 358 367 377 408 432 446 458 471 482 1385.33 1396.67 1231.00 1315.33 1321.67 1360.00 1240.67 1272.67 1269.00 1275.00 1088.00 917.00 1102.50 1001.33 818.00 833.67 896.67 893.00 834.00 829.33 750.00 669.67 625.00 440.00 642.00 598.50 547.50 563.00 559.50 1254.67 1233.33 1144.00 1173.67 1123.33 1289.00 1351.67 1396.67 1377.33 1177.33 957.33 1078.00 1161.33 1022.67 887.67 834.33 764.33 867.00 645.00 686.50 728.33 647.00 615.33 483.67 625.33 612.33 589.00 591.50 544.33 1175.67 1184.00 1168.33 1151.33 1154.67 1218.67 1191.33 1125.00 1104.33 1168.00 1084.67 1018.00 1027.67 993.33 932.33 932.67 828.00 843.33 699.33 720.67 737.33 693.00 628.00 607.67 762.67 665.67 624.67 568.00 537.33 1159.00 1150.00 1121.67 1121.33 1114.00 1165.00 1202.00 1127.67 1079.67 1012.33 1085.33 1020.33 1013.33 984.00 892.00 948.33 851.33 809.50 707.00 713.67 736.67 750.00 656.67 604.33 751.67 593.33 625.00 619.50 528.00 1189.67 1155.00 1159.67 1156.67 1140.33 1173.67 1182.00 1176.00 1143.33 1087.33 1104.33 1044.00 1012.50 988.50 993.00 991.00 935.67 885.33 800.67 719.00 761.00 786.33 697.00 725.00 702.50 550.50 600.00 537.00 515.00

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Appendix: Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Average value of TDS (mg/L) in all reactors

Date Day Feed Anaerobic Tank Anoxic Tank AMBR Permeate

12/02/2016 94 658.33 548.33 446.33 551.00

15/02/2016 97 797.00 852.67 759.67 803.11

17/02/2016 99 787.33 818.00 791.00 798.78

19/02/2016 101 856.00 749.33 786.00 797.11

22/02/2016 104 702.00 785.00 736.00 741.00

25/02/2016 107 929.67 757.67 747.67 811.67

1/03/2016 112 1076.33 811.00 853.33 913.56

7/03/2016 118 1098.67 922.00 935.67 985.44

12/03/2016 123 927.00 993.00 886.33 935.44

16/03/2016 127 891.00 923.67 858.67 891.11

18/03/2016 129 731.33 860.33 849.67 867.33 843.67

24/03/2016 135 1009.67 836.67 842.00 809.33 823.67

27/03/2016 138 926.33 910.00 820.00 841.00 850.33

13/04/2016 155 905.33 751.67 826.67 820.00 867.67

15/04/2016 157 894.00 775.33 815.67 800.33 821.33

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Appendix: Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

18/04/2016 160 879.33 832.00 791.33 791.00 817.33

20/04/2016 22/04/2016 1/06/2016 6/06/2016 14/06/2016 20/06/2016 27/06/2016 29/06/2016 1/07/2016 4/07/2016 20/07/2016 25/07/2016 28/07/2016 2/08/2016 16/08/2016 22/08/2016 26/08/2016 29/08/2016 1/09/2016 162 164 204 209 217 223 230 232 234 237 253 258 261 266 280 286 290 293 296 862.33 886.33 893.67 788.00 841.67 846.00 870.00 794.00 814.33 812.00 816.00 696.33 587.00 704.50 641.00 523.67 533.67 574.00 571.00 827.33 752.00 757.67 748.00 736.67 739.00 780.00 762.33 720.00 707.00 747.67 694.00 652.00 666.33 636.00 597.00 597.00 530.00 540.00 717.33 741.67 735.67 718.00 717.67 713.00 745.67 756.33 721.33 690.67 648.00 694.67 653.00 622.33 629.67 552.67 607.00 544.67 515.67 791.00 761.33 739.00 744.00 740.00 730.00 751.00 769.67 752.33 731.33 696.00 707.00 668.50 648.00 632.50 635.00 634.33 598.67 566.67 818.33 803.00 789.33 732.00 751.33 719.33 825.00 865.00 896.67 881.67 755.33 613.00 690.00 743.00 654.67 568.00 533.67 489.00 555.33

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Appendix: Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Average value of dissolved oxygen (mg/L) in all reactors

Day Feed Permeate

Date 17/11/2015 18/11/2015 19/11/2015 20/11/2015 23/11/2015 27/11/2015 30/11/2015 2/12/2015 4/12/2015 7/12/2015 9/12/2015 11/12/2015 15/12/2015 20/01/2016 22/01/2016 27/01/2016 29/01/2016 1/02/2016 15/02/2016 3/02/2016 5/02/2016 10/02/2016 12/02/2016 15/02/2016 17/02/2016 19/02/2016 22/02/2016 25/02/2016 1/03/2016 7/03/2016 12/03/2016 16/03/2016 18/03/2016 24/03/2016 27/03/2016 13/04/2016 15/04/2016 18/04/2016 22/04/2016 Anaerobic Tank Anoxic Tank AMBR 6.60 7.50 7.75 7.64 7.92 6.30 7.88 7.76 5.15 7.31 7.42 7.02 8.05 7.81 8.03 8.47 8.11 8.19 7.00 6.61 7.75 6.31 8.11 7.75 8.22 8.44 8.35 8.33 7.78 8.19 5.56 8.30 8.02 8.19 7.94 7.46 7.48 7.23 6.06 0.40 0.26 0.33 0.36 0.26 0.25 0.21 0.28 0.24 0.17 0.24 0.22 0.19 0.62 0.53 0.60 0.28 0.19 0.22 0.19 0.21 0.22 0.20 0.21 0.19 0.23 0.20 0.21 0.24 0.21 0.25 0.18 0.32 0.35 0.27 0.35 0.36 0.32 0.26 0.24 0.21 0.19 0.18 0.48 0.24 0.22 0.18 0.19 0.18 0.18 0.18 0.16 0.23 0.18 0.21 0.20 0.18 0.19 0.17 0.18 0.20 0.26 0.22 0.36 0.21 0.33 0.20 0.31 8.63 7.97 7.98 8.58 8.31 8.45 8.45 8.57 8.34 7.77 7.58 8.58 7.63 8.63 8.31 6.53 8.34 6.82 8.51 8.13 6.44 8.29 7.46 8.73 7 8 9 10 13 17 20 22 24 27 29 31 35 71 73 76 78 80 83 85 87 90 94 97 99 101 104 107 112 118 123 127 129 135 138 155 157 160 164 7.17 7.89 8.24 7.88 7.89 7.93 7.77

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Appendix: Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

1/06/2016 6/06/2016 14/06/2016 29/06/2016 1/07/2016 4/07/2016 16/08/2016 22/08/2016 29/08/2016 1/09/2016 8/09/2016 23/09/2016 29/09/2016 7/10/2016 10/10/2016 14/10/2016 2/11/2016 11/11/2016 21/11/2016 19/12/2016 22/12/2016 15/01/2017 29/01/2017 10/02/2017 6/03/2017 204 209 217 232 234 237 280 286 293 296 303 318 324 332 335 339 358 367 377 405 408 432 446 458 482 9.38 9.16 9.14 9.13 10.17 9.15 1.44 0.31 5.88 4.33 1.70 0.15 4.89 3.35 0.06 0.15 0.78 0.07 6.59 7.63 6.50 5.53 6.58 7.27 5.98 0.07 0.07 0.41 0.21 0.18 0.12 0.15 0.16 0.14 0.15 0.21 0.11 0.02 0.24 0.13 0.08 0.07 0.02 0.06 0.10 0.12 0.14 0.27 0.28 0.11 4.41 7.17 6.90 7.28 6.84 8.60 8.95 9.54 9.27 9.50 9.31 9.66 8.06 9.03 8.10 7.99 8.65 9.01 8.42 8.78 9.09 8.07 7.98 7.76 8.18 0.24 0.31 0.42 0.16 0.06 0.03 0.05 0.04 0.15 0.10 0.00 0.01 0.06 0.06 0.00 0.00 0.06 0.00 0.00 0.01 0.01 0.01 0.02 0.01 0.03 9.38 8.81 9.37 8.92 8.01 7.75 8.86 9.09 9.07 5.96 8.52 8.61 5.99 5.61 8.90 8.49 8.99 8.35 8.02 8.71 8.93 7.37 7.47 6.48 7.91

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Appendix: Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Average value of oxidation reduction potential (mV) in all reactors

Date Day Feed Anaerobic Tank Anoxic Tank AMBR Permeate

17/11/2015 18/11/2015 7 8 -369.55 -378.43 157.00 184.27

19/11/2015 20/11/2015 23/11/2015 27/11/2015 30/11/2015 2/12/2015 4/12/2015 7/12/2015 9/12/2015 11/12/2015 15/12/2015 20/01/2016 22/01/2016 25/01/2016 29/01/2016 1/02/2016 3/02/2016 5/02/2016 10/02/2016 12/02/2016 15/02/2016 17/02/2016 19/02/2016 22/02/2016 25/02/2016 1/03/2016 7/03/2016 12/03/2016 16/03/2016 18/03/2016 24/03/2016 27/03/2016 13/04/2016 15/04/2016 18/04/2016 20/04/2016 22/04/2016 9 10 13 17 20 22 24 27 29 31 35 71 73 76 78 80 83 85 87 90 94 97 99 101 104 107 112 118 123 127 129 135 138 155 157 160 162 19.95 -37.13 35.30 50.97 20.93 -24.17 48.55 35.50 -70.83 -29.40 -66.17 -32.35 13.63 -5.73 3.97 17.30 102.83 75.40 10.70 -1.90 133.53 262.75 84.63 -374.70 -364.33 -367.10 -353.20 -367.63 -341.87 -337.67 -333.85 -330.75 -323.15 -326.05 -76.80 -187.20 -32.75 -348.40 -352.27 -344.37 -344.27 -349.80 -339.90 -342.90 -341.63 -358.37 -351.80 -337.70 -344.67 -339.00 -339.03 -344.43 -351.00 -315.57 -340.17 -336.47 -313.07 -322.73 -301.87 -309.43 -335.35 -336.15 -315.55 -356.90 -91.70 -49.00 -334.80 -340.30 -344.70 -355.13 -355.40 -361.60 -319.63 -239.93 -337.17 -357.90 -211.37 -324.10 -347.17 -364.07 -322.27 -206.53 -216.17 -348.17 -327.70 -311.77 -317.93 -295.93 -286.63 105.90 33.60 -67.93 17.03 -34.40 -14.30 46.60 76.30 69.90 97.30 69.60 29.20 -14.40 44.25 25.00 35.00 17.17 51.57 93.27 -54.77 40.73 -10.67 117.60 105.43 9.83 -64.63 71.75 -5.90 31.83 -6.00 46.40 37.23 67.37 155.10 -77.63 90.47 8.05 62.17 52.83 90.00 25.00 129.73 114.93 71.20

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Appendix: Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

1/06/2016 6/06/2016 22/08/2016 29/08/2016 1/09/2016 8/09/2016 23/09/2016 29/09/2016 7/10/2016 10/10/2016 14/10/2016 2/11/2016 11/11/2016 21/11/2016 19/12/2016 22/12/2016 15/01/2017 23/02/2017 6/03/2017 164 204 280 290 293 300 318 324 332 335 339 358 367 377 405 408 432 471 482 59.13 69.20 -523.37 -123.55 -39.60 -42.50 -399.97 -143.90 -116.05 -198.70 -228.20 -24.95 -130.10 -175.50 -176.15 24.70 56.75 80.75 -178.00 -282.80 -346.00 -410.80 -182.37 -256.93 -270.33 -84.33 -248.00 -245.93 -269.67 -206.80 -207.87 -241.60 -228.30 -217.03 -225.57 -235.85 -230.65 -215.90 162.53 69.23 199.00 161.33 -22.50 90.53 122.40 26.57 69.10 22.93 125.83 149.73 38.20 113.13 168.57 28.00 161.50 37.80 29.40 187.37 148.07 214.13 186.07 115.87 108.33 14.97 121.60 113.45 30.07 140.23 161.20 19.77 172.30 174.20 140.00 140.50 43.00 45.25 -308.13 -331.55 -465.97 -243.03 -265.37 -271.07 -221.80 -251.60 -215.13 -266.95 -218.00 -213.17 -221.40 -190.07 -217.63 -198.40 -177.25 -188.25 -170.17

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Appendix: Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Average value of temperature (ͦC) in all reactors

Date Day Feed Anaerobic Anoxic AMBR Permeate

20.85 19.15

17/11/2015 18/11/2015 19/11/2015 20/11/2015 23/11/2015 25/11/2015 27/11/2015 30/11/2015 2/12/2015 4/12/2015 7/12/2015 9/12/2015 11/12/2015 15/12/2015 20/01/2016 22/01/2016 25/01/2016 27/01/2016 29/01/2016 1/02/2016 3/02/2016 5/02/2016 10/02/2016 12/02/2016 15/02/2016 17/02/2016 19/02/2016 22/02/2016 25/02/2016 1/03/2016 7/03/2016 12/03/2016 18/03/2016 24/03/2016 27/03/2016 13/04/2016 15/04/2016 18/04/2016 20/04/2016 22/04/2016 1/06/2016 7 8 9 10 13 15 17 20 22 24 27 29 31 35 71 73 76 78 80 83 85 87 92 94 97 99 101 104 107 112 118 123 129 135 138 155 157 160 162 164 204 18.90 20.20 19.40 18.77 20.00 19.87 19.53 19.87 19.83 21.13 20.20 18.87 20.60 19.83 20.43 22.27 20.47 20.33 19.60 18.77 19.30 18.67 20.10 19.20 16.70 22.05 23.10 25.67 24.37 21.90 24.40 22.10 24.27 23.17 23.83 25.90 25.15 22.15 21.30 25.50 24.00 24.30 24.50 22.60 21.70 23.53 22.73 23.00 22.40 22.40 21.80 22.23 23.17 23.87 24.10 23.87 24.13 24.47 23.57 22.47 21.27 21.67 20.30 24.03 21.80 17.73 28.80 26.40 26.20 28.60 27.70 24.60 28.55 26.87 24.83 27.47 26.80 26.90 26.03 25.47 25.10 26.50 26.70 27.50 28.03 27.90 28.33 28.27 27.17 26.53 23.77 25.23 24.25 26.90 24.20 20.85 19.40 19.60 21.67 20.57 18.60 20.07 18.23 18.93 18.33 20.00 21.07 21.80 20.20 19.50 22.70 21.70 24.60 21.45 19.90 18.83 21.60 20.00 20.17 19.60 19.70 18.70 19.37 19.83 21.00 21.07 21.50 22.00 21.30 21.10 18.97 18.93 19.10 19.00 20.07 19.97 16.40 20.87 20.50 18.47 18.80 18.70 18.70 19.40 18.90 14.85

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Appendix: Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

6/06/2016 8/06/2016 14/06/2016 20/06/2016 27/06/2016 29/06/2016 1/07/2016 4/07/2016 20/07/2016 25/07/2016 28/07/2016 2/08/2016 16/08/2016 22/08/2016 26/08/2016 29/08/2016 1/09/2016 8/09/2016 29/09/2016 7/10/2016 10/10/2016 2/11/2016 19/12/2016 15/01/2017 10/02/2017 23/02/2017 6/03/2017 209 211 217 223 230 232 234 237 253 258 261 266 280 286 290 293 296 303 324 332 335 358 405 432 458 471 482 16.75 16.50 17.57 17.10 15.60 17.35 15.50 18.15 17.80 14.30 19.90 15.60 19.73 15.20 11.40 10.20 11.60 19.00 16.50 17.50 18.75 20.75 26.50 28.00 24.25 23.25 26.25 21.93 17.00 18.90 22.10 19.63 20.80 20.43 23.30 22.40 20.30 20.60 20.63 22.57 21.57 21.57 22.15 22.15 27.00 21.50 24.50 26.25 28.50 27.50 24.50 27.75 27.00 29.37 16.90 17.00 15.40 16.75 13.80 15.23 14.60 16.20 16.65 14.50 14.70 14.60 16.40 15.30 14.40 15.27 15.80 25.75 24.50 26.25 25.00 25.75 28.50 28.00 26.50 30.00 25.65 16.30 16.40 14.83 16.50 13.57 17.23 14.30 15.95 16.50 14.33 14.20 14.50 16.35 14.95 14.60 14.70 15.50 20.75 18.75 18.75 20.00 20.50 21.50 21.00 22.00 23.75 24.25 17.50 17.75 16.10 18.20 16.63 17.24 17.20 19.10 18.57 17.50 17.10 17.00 18.93 17.90 17.60 17.75 18.35 23.50 20.50 23.50 21.75 25.33 24.00 28.00 27.50 24.50 26.50

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Appendix: Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Permeate flow, recirculation flow, flux, HRT, TMP and permeate turbidity during treating the car wash wastewater with eMBR

Date Day Recirculation rate (L/d) Flux (L/m2h) HRT (day) TMP (kPa) Turbidity (NTU) Permeate Flow (L/d)

187.68 30.00 0.389 27/03/2016 138 2.00 6.56 150.14 37.50 0.194 20/04/2016 162 4.00 8.20 2.50 312.80 29.00 0.154 1/06/2016 204 3.50 3.94 1.20 170.62 35.00 0.271 20/06/2016 223 3.50 7.22 2.20 187.68 32.00 0.321 1/07/2016 234 3.50 6.56 2.00 130.33 40.00 0.165 20/07/2016 253 4.61 9.45 2.88 110.28 32.50 0.315 25/07/2016 258 7.51 11.17 3.40 117.30 33.50 0.104 28/07/2016 261 3.20 10.50 181.33 31.00 0.142 2/08/2016 266 2.07 4.80 6.79 129.43 31.00 0.176 5/08/2016 269 2.90 9.51 170.62 38.00 0.229 18/08/2016 282 4.50 7.22 2.20 183.10 35.00 0.244 26/08/2016 290 6.73 2.05 183.14 35.00 0.155 29/08/2016 293 6.72 2.05 187.68 37.00 0.396 1/09/2016 296 6.56 2.00 197.56 32.00 0.297 8/09/2016 303 6.23 1.90 200.51 35.00 0.350 29/09/2016 324 3.50 6.14 1.87 208.53 35.00 0.256 3/10/2016 328 3.50 5.91 1.80 288.74 35.00 0.224 7/10/2016 332 4.27 1.30 178.74 0.00 0.501 10/10/2016 335 6.89 2.10 217.22 29.00 0.318 17/10/2016 342 5.67 1.73 229.55 38.00 0.325 11/11/2016 367 3.20 5.36 1.64 300.29 40.00 0.465 15/01/2017 432 3.00 4.10 1.25

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Appendix: Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

187.59 0.00 463 15/02/2017 1.5 5.05 92.37 55.00 0.978 468 20/02/2017 3.1 10.25 93.34 55.00 1.080 469 21/02/2017 3.1 10.15 91.90 58.00 1.020 470 22/02/2017 3.1 10.31 94.76 52.00 0.877 472 24/02/2017 3.0 5.50 10.00 93.98 48.00 0.763 475 27/02/2017 3.1 10.08 94.35 50.00 0.710 477 1/03/2017 3.1 10.04 96.24 42.00 0.855 479 3/03/2017 3.0 9.84 93.36 47.00 0.789 481 5/03/2017 3.1 10.15 91.53 50.00 0.413 482 6/03/2017 3.2 10.35 100.25 50.00 0.540 485 9/03/2017 2.9 9.45 112.45 50.00 0.401 486 10/03/2017 2.6 8.42 98.82 50.00 0.528 487 11/03/2017 2.9 9.59 100.97 51.00 0.492 489 13/03/2017 2.9 9.38

Average value of COD (mg/L) in all reactors

Date Day Feed Anaerobic Anoxic AMBR Permeate

14/04/2016 21/04/2016 3/06/2016 2/08/2016 17/08/2016 156 163 206 266 281 898.50 953.00 980.50 1061.00 476.50 357.00 202.50 115.50 257.00 146.50 155.00 109.50 20.50 115.50 74.00 16.00 30.00 15.00 58.50 48.00 8.00 12.50 10.00 8.00 6.50

112.00 193.00 173.00 187.50 204.00 178.00 276.50 75.00 133.50 109.50 74.00 161.50 106.00 200.00 51.00 72 54 53.5 52.5 68 64.5

1/09/2016 23/09/2016 8/10/2016 3/11/2016 21/11/2016 14/12/2016 7/03/2017 14/03/2017 296 318 333 359 377 398 481 488 437.00 759.50 186.50 314.50 352.50 165.00 510.50 429.50 5.50 1.50 11.00 1.50 0.00 0.00 4.50 1.50

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Appendix: Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Average value of total nitrogen (mg/L) in all reactors

Date Day Feed Anaerobic Anoxic AMBR Permeate

6.00 12.00 35.00 17.00 23.00 24.00 14.00 5.00 9.00 18.00 6.20 3.00 5.50 57.50 0.00 9.00 11.00 12.00 9.00 4.00 9.00 2.90 8.00 4.00 19.00 1.00 16.00 5.00 7.00 9.00 4.00 7.00 2.70

14/04/2016 21/04/2016 3/06/2016 2/08/2016 17/08/2016 1/09/2016 23/09/2016 8/10/2016 3/11/2016 14/12/2016 7/03/2017 14/03/2017 156 163 206 266 281 296 318 333 359 398 481 488 10.50 13.50 53.00 37.00 24.00 15.00 19.00 11.00 11.00 16.00 9.50 9.60 5.50 2.00 21.50 3.00 10.00 6.00 5.00 5.60 4.00 6.00 3.20 4.40

3-P (mg/L) in all reactors

Average value of total phosphorus PO4

Date Day Feed Anaerobic Anoxic AMBR Permeate

11.27 14.69 17.97 14.38 11.03 13.53 4.35 5.56 2.91 2.45 1.80 16.75 19.84 23.09 14.62 16.11 11.91 15.11 12.19 0.98 7.94 6.34 1.27 20.11 21.05 19.54 17.75 18.37 22.21 17.45 15.39 8.24 7.29 7.55 2.71 15.83 21.54 19.54 17.09 21.57 21.90 20.26 14.31 12.32 5.23 7.35 1.96 14.85

14/04/2016 21/04/2016 3/06/2016 2/08/2016 17/08/2016 1/09/2016 23/09/2016 8/10/2016 3/11/2016 21/11/2016 14/12/2016 7/03/2017 14/03/2017 156 163 206 266 281 296 318 333 359 377 398 481 488 23.59 21.41 14.25 19.48 20.96 18.64 18.27 12.52 5.23 5.56 1.67 14.36 20.33

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Appendix: Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Average value of Ammonia NH3-N (mg/L) in all reactors

Date Day Feed AMBR Permeate Anaerobic Tank Anoxic Tank

6.6 21.15 44.7 20.5 11.4 6.3 0.6 2 4.4 3.1 3.95 19.85 0 10.9 3.5 2.2 4.8 1.3 4.5 1.6 0.15 0.4 0.2 0.45 0.4 1.2 0.7 0.5 NA 0.1

14/04/2016 3/06/2016 4/07/2016 21/07/2016 1/09/2016 23/09/2016 8/10/2016 3/11/2016 14/12/2016 7/03/2017 14/03/2017 156 206 237 254 296 318 333 359 398 481 488 13.35 42.60 26.50 33.70 2.60 10.7 1.70 1.90 6.70 3.1 2.15 0.15 0.75 0.4 0.35 0.4 0.15 0.6 0.1 0.5 0 0.1

Average value of Nitrite NO2-N (mg/L) in all reactors

Date Day Feed Anaerobic Tank Anoxic Tank AMBR Permeate

4.26 0.18 0.05 0.09 0.06 4.87 0.26 1.22 3.65 0.37 0.26 0.05 0.06 0.10 7.03 0.48 NA 2.44 0.00 0.00 0.09 0.09 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.06 0.09 0.00 10.35 0.00 0.00 11.27 1.98 0.05 0.06 0.06 3.65 7.31 3.65 4.05 8.83 3/06/2016 20/06/2016 4/07/2016 21/07/2016 8/10/2016 3/11/2016 21/11/2016 14/12/2016 6/03/2017 206 223 237 254 333 359 377 398 480

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Appendix: Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Average value of Nitrate NO3-N (mg/L) in all reactors

Date Day Feed Anaerobic Tank Anoxic Tank AMBR Permeate

0 7.9 0

2.20 0.10

14/04/2016 3/06/2016 16/06/2016 20/06/2016 4/07/2016 21/07/2016 1/09/2016

11.7 7 8.5 0.7 0.3 1 1.2 0.8 3.1 1.3 2.3 0.1 0 1 2.2 3 5.7

156 206 219 223 237 254 296 318 333 359 377 398 480 NA 5.30 NA 7.00 3.20 5.20 NA 17.3 4.75 0.90 0.3 0.2 0.65 2.9 1.7 NA 13.7 6.8 7.6 7.5 2.8 0.2 3.6 15.1 1.2 2.2 2.2 0.6 1.8 1.5 1.3 2.4 4.7 1.4 6.3 0.6 0.4 0.2 0 23/09/2016 8/10/2016 3/11/2016 21/11/2016 14/12/2016 6/03/2017

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MLSS

Date Volume (L) Blank (g) Blank+Fliter (g) B+F+Solids (g) MLSS (g/L) After 105 ͦC dry in the oven Average MLSS (g/L)

2.761

4.352

Anaerobic Anoxic Tank AMBR 2.508 2.480 2.484 2.501 0.925 2.566 2.595 2.567 2.572 2.588 1.012 2.653 3.967 3.512 3.993 3.361 1.209 2.782 2.663 2.609 2.654 2.681 1.019 2.661 0.020 0.020 0.020 0.020 0.020 0.020 3.426 2.096 4.091 4.614 0.368 0.374 0.371

21/07/2016 Started to introduce the 25% carwash on 22 July 2016

2/08/2016 2.300

3.450

0.300

2.125

4.225

11/08/2016 0.225

2.075

16/08/2016 Anaerobic Anoxic Tank AMBR Anaerobic Anoxic AMBR Anaerobic Anoxic AMBR 2.503 2.482 0.924 2.565 2.571 2.571 2.502 0.924 2.572 2.483 2.572 2.567 2.564 2.565 0.925 2.566 2.573 2.594 2.571 1.013 2.657 2.663 2.660 2.592 1.016 2.664 2.574 2.663 2.658 2.657 2.657 1.017 2.658 2.665 2.804 3.004 1.851 3.252 2.829 2.812 3.596 1.600 4.387 4.118 2.685 2.696 3.597 3.781 2.277 4.087 2.733 2.611 2.600 1.042 2.697 2.664 2.665 2.619 1.074 2.775 2.632 2.669 2.661 2.682 2.715 1.112 2.735 2.672 0.010 0.010 0.010 0.010 0.010 0.010 0.020 0.020 0.020 0.020 0.020 0.020 0.020 0.020 0.020 0.020 0.020 1.700 2.900 2.900 4.000 0.100 0.500 1.350 2.900 5.550 2.900 0.300 0.150 1.250 2.900 4.750 3.850 0.350 4.300 0.200

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2.572 2.664 2.748 2.665 0.020 0.050

Started to introduce the 50% carwash on 18 August 2016

1.075

3.800

26/08/2016 0.150

1/09/2016 1.225

4.675

0.075

8/09/2016 0.925

5.200

Anaerobic Anoxic AMBR Anaerobic Anoxic AMBR Anaerobic Anoxic AMBR 2.564 2.565 0.925 2.566 2.572 2.572 2.565 2.566 0.925 2.566 2.573 2.573 2.566 2.566 0.925 2.565 2.574 2.573 2.650 2.651 1.011 2.653 2.658 2.659 2.652 2.652 1.012 2.653 2.660 2.660 2.656 2.657 1.016 2.657 2.664 2.664 3.216 2.928 2.016 3.471 2.847 2.831 2.673 3.263 1.929 3.511 2.774 2.754 2.670 2.681 3.184 4.146 2.803 2.798 2.678 2.666 1.090 2.726 2.662 2.661 2.671 2.682 1.102 2.750 2.661 2.662 2.674 2.676 1.123 2.758 2.667 2.666 0.020 0.020 0.020 0.020 0.020 0.020 0.020 0.020 0.020 0.020 0.020 0.020 0.020 0.020 0.020 0.020 0.020 0.020 1.400 0.750 3.950 3.650 0.200 0.100 0.950 1.500 4.500 4.850 0.050 0.100 0.900 0.950 5.350 5.050 0.150 0.100 0.125

Started to introduce the 75% carwash on 13 September 2016

0.275

3.475

Anaerobic Anoxic AMBR

23/09/2016 29/09/2016 Anaerobic 2.547 2.547 2.551 2.538 2.549 3.657 2.546 2.637 2.638 2.642 2.629 2.640 3.748 2.637 2.634 2.645 3.212 3.259 2.790 3.941 4.217 2.642 2.644 2.736 2.674 2.642 3.749 2.695 0.020 0.020 0.020 0.020 0.020 0.020 0.020 0.250 0.300 4.700 2.250 0.100 0.050 2.900 0.075 2.250

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1.625

0.175

7/10/2016 2.725

1.325

Anoxic AMBR Anaerobic Anoxic AMBR 2.548 2.550 2.538 2.549 3.656 2.546 2.548 2.551 2.538 2.549 3.656 2.638 2.641 2.630 2.640 3.747 2.632 2.633 2.637 2.624 2.633 3.742 2.873 2.803 2.793 2.831 3.960 2.804 2.784 2.774 2.814 2.743 3.888 2.670 2.692 2.644 2.643 3.751 2.706 2.668 2.640 2.674 2.643 3.750 0.020 0.020 0.020 0.020 0.020 0.020 0.020 0.020 0.020 0.020 0.020 1.600 2.550 0.700 0.150 0.200 3.700 1.750 0.150 2.500 0.500 0.400 0.450

Started to introduce the 100% carwash on 10 October 2016

1.150

3.425

20/10/2016 0.250

2/11/2016 0.300

4.250

0.300

0.400

21/11/2016 Anaerobic Anoxic AMBR Anaerobic Anoxic AMBR Anaerobic Anoxic 3.654 3.658 3.658 2.536 2.549 3.656 3.655 3.660 3.660 2.540 2.550 3.657 3.654 3.659 3.659 2.539 3.741 3.745 3.746 2.623 2.635 3.743 3.741 3.746 3.746 2.625 2.640 3.758 3.744 3.750 3.749 2.629 3.956 3.984 4.495 3.673 3.643 3.750 3.771 3.751 4.168 3.923 2.647 3.758 3.945 3.926 6.709 4.308 3.764 3.768 3.803 2.703 2.640 3.748 3.750 3.749 3.834 2.707 2.645 3.765 3.752 3.758 3.871 2.728 0.020 0.020 0.020 0.020 0.020 0.020 0.020 0.020 0.020 0.020 0.020 0.020 0.020 0.020 0.020 0.020 1.150 1.150 2.850 4.000 0.250 0.250 0.450 0.150 4.400 4.100 0.250 0.350 0.400 0.400 6.100 4.950 5.525

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2.654 3.792 0.450

1.650

3.775

25/01/2017 0.175

7/03/2017 3.770

6.462

AMBR Anaerobic Anoxic AMBR Anaerobic Anoxic AMBR 2.550 3.657 3.653 3.657 0.926 3.663 0.924 3.661 3.661 65.665 3.663 59.788 71.826 78.407 2.641 3.747 3.744 3.748 1.014 3.752 1.017 3.747 3.747 65.756 3.755 59.878 71.917 78.494 4.046 66.016 5.068 60.492 72.085 78.636 2.649 3.757 3.772 3.786 1.114 3.803 1.018 3.753 3.834 65.820 3.912 59.980 71.922 78.499 0.020 0.020 0.020 0.020 0.020 0.020 0.020 0.020 0.020 0.020 0.020 0.020 0.020 0.020 0.400 0.500 1.400 1.900 5.000 2.550 0.050 0.300 4.360 3.180 7.825 5.100 0.265 0.235 0.250

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Appendix: Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Critical flux Synthetic wastewater (continuous mode) (Phase 1)

Flow (L/h) Flux (L/m2h) Volume collected in (mL) Time (min) TMP (KPa)

0.00 0.0000 0.00 0 31

3.80 0.0456 3.59 5 31

15.40 0.1392 10.96 10 31

23.80 0.1008 7.94 15 31

27.60 0.0456 3.59 20 31

0.00 0.0816 6.43 22.5 35

6.80 0.1632 12.85 25 35

17.60 0.1296 10.20 30 35

22.50 0.0588 4.63 35 35

33.50 0.1320 10.39 40 35

0.00 0.0936 7.37 42.5 40

7.80 0.1872 14.74 45 40

17.90 0.1212 9.54 50 40

23.50 0.0672 5.29 55 40

33.00 0.1140 8.98 60 40

Critical flux 25% Car wash wastewater (continuous mode) (Phase 2)

Flow (mL/h) Flux(L/m2h) Time (min) TMP (KPa) Volume collected in (mL)

0 2 4 6 8 10 12 14 16 29 29 29 29 29 29 29 29 29 0.00 1.92 4.29 7.06 10.19 13.28 16.49 21.18 22.76 0.0000 0.0576 0.0711 0.0831 0.0939 0.0927 0.0963 0.1407 0.0474 0.00 4.54 5.60 6.54 7.39 7.30 7.58 11.08 3.73

A-32

Appendix: Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

18 20 22 24 26 28 30 29 29 29 29 29 29 29 0.0966 0.0954 0.0966 0.0912 0.0924 0.0951 0.0960 7.61 7.51 7.61 7.18 7.28 7.49 7.56 25.98 29.16 32.38 35.42 38.50 41.67 44.87

32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 37 37 37 37 38 38 38 38 38 38 38 38 38 38 38 0.1275 0.1401 0.1047 0.1221 0.1068 0.1428 0.1287 0.1152 0.1854 0.1251 0.0723 0.1170 0.1275 0.1281 0.1185 10.04 11.03 8.24 9.61 8.41 11.24 10.13 9.07 14.60 9.85 5.69 9.21 10.04 10.09 9.33 49.12 53.79 57.28 61.35 64.91 69.67 73.96 77.80 83.98 88.15 90.56 94.46 98.71 102.98 106.93

62 64 66 68 70 72 74 76 78 80 82 84 86 88 90 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 0.1431 0.1392 0.1269 0.0648 0.1983 0.1086 0.1170 0.1332 0.1218 0.1374 0.1257 0.1368 0.1296 0.1434 0.1050 11.27 10.96 9.99 5.10 15.61 8.55 9.21 10.49 9.59 10.82 9.90 10.77 10.20 11.29 8.27 111.70 116.34 120.57 122.73 129.34 132.96 136.86 141.30 145.36 149.94 154.13 158.69 163.01 167.79 171.29

A-33

Appendix: Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Critical flux 50% Car wash wastewater (continuous mode) (Phase 3)

TMP (KPa) Flux(L/m2h) Time (min) Volume collected in (mL) Flow (mL/h)

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38.38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72 74 76 34 34 34 34 34 34 34 34 34 34 34 34 34 34 34 34 37.5 37.5 38 38 39 39 39 39 39 39 39 39 39 39 39 39 39 39 39 39 39 39 39 0.00 3.19 6.21 9.81 13.85 17.89 21.65 26.01 29.55 33.60 37.86 41.48 45.88 49.95 54.72 57.94 62.66 67.62 72.54 76.97 80.51 84.97 89.84 94.01 98.89 103.18 107.12 111.79 115.89 120.42 124.65 128.99 133.48 138.86 142.54 147.13 151.58 156.11 160.59 0.00 0.10 0.09 0.11 0.12 0.12 0.11 0.13 0.11 0.12 0.13 0.11 0.13 0.12 0.14 0.10 0.14 0.15 0.15 0.11 0.13 0.13 0.15 0.13 0.15 0.13 0.12 0.14 0.12 0.14 0.13 0.13 0.13 0.16 0.11 0.14 0.13 0.14 0.13 0.00 7.54 7.13 8.50 9.54 9.54 8.88 10.30 8.36 9.57 10.06 8.55 10.39 9.61 11.27 7.61 11.15 11.72 11.62 8.79 10.32 10.54 11.50 9.85 11.53 10.13 9.31 11.03 9.69 10.70 9.99 10.25 10.61 12.71 8.69 10.84 10.51 10.70 10.58

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Appendix: Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

78 80 82 84 86 88 90 39 39 39 39 39 39 39 165.20 169.61 174.65 179.67 183.68 188.21 192.78 0.14 0.13 0.15 0.15 0.12 0.14 0.14 10.89 10.42 11.91 11.86 9.47 10.70 10.80

Critical flux 75% Car wash wastewater (continuous mode) (Phase 4)

Flux (L/m2h) Volume collected in (mL) Flow (mL/h) Time (min) TMP (KPa)

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36.31 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 27 27 27 27 27 27 27 27 27 27 27 27 27 27 27 27 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 37 37 37 0.00 0.99 2.73 5.26 8.14 11.13 14.38 17.74 21.29 24.21 27.41 30.76 34.04 37.30 40.58 43.68 47.79 54.33 58.81 62.42 66.72 71.26 75.04 79.42 83.67 88.12 92.40 96.87 101.25 105.52 109.68 115.40 119.98 124.09 0.00 29.70 52.20 75.90 86.40 89.70 97.50 100.80 106.50 87.60 96.00 100.50 98.40 97.80 98.40 93.00 123.30 196.20 116.36 128.17 129.00 136.20 113.40 131.40 127.50 133.50 128.40 134.10 131.40 128.10 124.80 171.60 137.40 123.30 0.00 2.34 4.11 5.98 6.80 7.06 7.68 7.94 8.39 6.90 7.56 7.91 7.75 7.70 7.75 7.32 9.71 15.45 9.16 10.09 10.16 10.72 8.93 10.35 10.04 10.51 10.11 10.56 10.35 10.09 9.83 13.51 10.82 9.71

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Appendix: Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

128.77 133.73 138.50 147.48 150.09 152.82 157.62 165.62 169.65 172.86 177.07 181.32 140.40 148.80 143.10 146.41 118.64 163.80 144.00 240.00 80.60 192.60 126.30 127.50 11.06 11.72 11.27 11.53 9.34 12.90 11.34 18.90 6.35 15.17 9.94 10.04 68 70 72 75.68 77 78 80 82 85 86 88 90 37.5 38 40 40 40 40 40 40 40 40 40 40

Critical flux 100% Car wash wastewater (continuous mode) (Phase 5)

TMP (KPa) Flux (L/m2h) Time (min) Flow (mL/h) Volume collected in (mL)

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 40 42 44 46 48 50 52 54 20 25 28 30 30 30 29 29 30 30 32 32 32 32 32 32 35 35 35 35 37.5 37.5 37.5 38 38 38 38 0.00 0.06 0.12 0.18 0.24 0.30 0.37 0.45 0.68 1.23 2.67 4.40 6.81 10.47 12.26 15.45 18.16 22.22 27.63 30.52 34.42 38.70 43.28 45.46 48.59 52.08 55.27 0.00 1.80 1.80 1.80 1.80 1.80 2.10 2.40 6.90 16.50 43.20 51.90 72.30 109.80 53.70 95.70 81.30 121.80 162.30 43.35 117.00 128.40 137.40 65.40 93.90 104.70 95.70 0.00 0.14 0.14 0.14 0.14 0.14 0.17 0.19 0.54 1.30 3.40 4.09 5.69 8.65 4.23 7.54 6.40 9.59 12.78 3.41 9.21 10.11 10.82 5.15 7.39 8.24 7.54

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Appendix: Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

56 58 60 62 64 66 68 70 72 74 76 78 80 82 84 86 88 90 38 38 38 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 101.70 98.10 107.10 97.50 107.10 115.20 105.60 97.20 67.50 108.60 101.10 92.10 98.70 64.80 77.70 42.60 65.40 62.40 8.01 7.72 8.43 7.68 8.43 9.07 8.31 7.65 5.31 8.55 7.96 7.25 7.77 5.10 6.12 3.35 5.15 4.91 58.66 61.93 65.50 68.75 72.32 76.16 79.68 82.92 85.17 88.79 92.16 95.23 98.52 100.68 103.27 104.69 106.87 108.95

Critical flux 100% Car wash wastewater (After reducing HRT) (continuous mode) (Phase 6)

Flux (L/m2h) Time (min) TMP (KPa) Flow (mL/h) Volume collected in (mL)

0 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 40 46 50 50 50 52 53 53 53 53 53 53 53 53 53 55 57 58 58 58 0.00 0.00 22.03 330.45 29.72 230.70 35.35 168.90 40.68 159.90 45.57 146.70 50.26 140.70 55.03 143.10 60.16 153.90 65.10 148.20 70.44 160.20 75.75 159.30 81.01 157.80 86.18 155.10 91.74 166.80 97.36 168.60 102.91 166.50 108.40 164.70 114.26 175.80 120.25 177.75 0.00 0.00 18.17 13.30 12.59 11.55 11.08 11.27 12.12 11.67 12.61 12.54 12.43 12.21 13.13 13.28 13.11 12.97 13.84 14.00

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Appendix: Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Critical flux Synthetic wastewater (intermittent mode) (Phase 1)

42 44 48 50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80 82 84 86 88 90 58 58 58 59 59 60 60 60 60 62 62 62 62 62 62.5 62.5 62.5 62.5 62.5 62.5 62.5 62.5 62.5 62.5 12.47 14.76 12.93 13.51 13.63 13.61 11.24 18.05 12.24 13.30 14.76 13.44 14.60 15.07 10.28 15.92 13.65 13.51 15.40 13.96 13.32 14.74 13.58 13.28 125.53 158.40 131.78 187.50 142.73 164.25 148.45 171.60 154.22 173.10 159.98 172.80 164.74 142.80 172.38 229.20 177.56 155.40 183.19 168.90 189.44 187.50 195.13 170.70 201.31 185.40 207.69 191.40 212.04 130.50 218.78 202.20 224.56 173.40 230.28 171.60 236.80 195.60 242.71 177.30 248.35 169.20 254.59 187.20 260.34 172.50 265.96 168.60

Flow (L/h) Flux (Lm2.h) Time (min) TMP (KPa) Volume collected in (L)

0 3.58 5 6.13 9.21 10 15 16.38 18.49 20 35 0 0 0 35 35 35 0 0 22.5 0.00000 0.00609 0.00850 0.01042 0.01566 0.01700 0.02550 0.02785 0.03143 0.03400 0.00 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.00 8.03 8.03 8.03 8.03 8.03 8.03 8.03 8.03 8.03

21.41 35 0.00254 0.11 8.50

22.21 37.5 0.00398 0.11 8.50

25 37.5 0.00900 0.11 8.50

29.18 0 0.01652 0.11 8.50

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Appendix: Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

30 0 0.01800 0.11 8.50

31.13 0 0.02003 0.11 8.50

34.34 37.5 0.02581 0.11 8.50

35 37.5 0.02700 0.11 8.50

40 37.5 0.03600 0.11 8.50

42.08 38.25 0.00343 0.10 7.80

42.08 0 0.00343 0.10 7.80

43.58 0 0.00591 0.10 7.80

45 35 0.00825 0.10 7.80

47 40 0.01155 0.10 7.80

50 40 0.01650 0.10 7.80

54.38 40 0.02373 0.10 7.80

54.38 0 0.02373 0.10 7.80

56.49 0 0.02721 0.10 7.80

59.21 60 40 40 0.10 0.10 7.80 7.80 0.03170 0.03300

Critical flux 25% Car wash wastewater (intermittent mode) (Phase 2)

Flux(l/m2.h) Time (min) TMP (KPa) Flow (L/d) Volume collected in (mL)

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 21 27 29 30 30 0 20 29 30 30 30 0 19 25 29 30 0.000 0.00 0.980 0.03 2.260 0.04 4.620 0.07 7.520 0.09 9.800 0.07 12.090 0.07 15.260 0.10 17.700 0.07 20.640 0.09 23.940 0.10 26.670 0.08 28.880 0.07 32.060 0.10 34.340 0.07 37.180 0.09 0.00 2.31 3.02 5.57 6.85 5.39 5.41 7.49 5.76 6.94 7.80 6.45 5.22 7.51 5.39 6.71

32 34 36 38 37.5 0 28 37.5 41.460 0.13 45.020 0.11 47.780 0.08 51.810 0.12 10.11 8.41 6.52 9.52

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Appendix: Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80 82 84 86 88 90 92 94 96 98 100 37.5 37.5 37.5 0 25 37.5 37.5 37.5 37.5 0 37.5 40 40 40 40 0 8 40 40 40 40 0 0 40 40 40 40 40 0 39 40 6.54 8.15 9.90 10.20 6.61 10.91 7.25 7.51 9.52 9.71 6.40 12.14 7.70 7.80 10.18 10.89 7.13 11.34 7.54 8.13 9.24 10.61 7.20 11.86 10.30 6.09 9.69 10.75 8.08 11.57 7.16 54.580 0.08 58.030 0.10 62.220 0.13 66.540 0.13 69.340 0.08 73.960 0.14 77.030 0.09 80.210 0.10 84.240 0.12 88.350 0.12 91.060 0.08 96.200 0.15 99.460 0.10 102.760 0.10 107.070 0.13 111.680 0.14 114.700 0.09 119.500 0.14 122.690 0.10 126.130 0.10 130.040 0.12 134.530 0.13 137.580 0.09 142.600 0.15 146.960 0.13 149.540 0.08 153.640 0.12 158.190 0.14 161.610 0.10 166.510 0.15 169.540 0.09

Critical flux 50% Car wash wastewater (intermittent mode) (Phase 3)

Flow (L/d) Time (min) TMP (KPa) Flux (L/m2.h) Volume collected in (mL)

0 2 4 6 8 10.57 12 32.5 33 33 33 0 19 27 0.000 2.750 4.970 7.450 10.450 14.410 16.390 0.00 1.98 1.60 1.79 2.16 2.22 1.99 0.00 6.50 5.24 5.86 7.09 7.28 6.54

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Appendix: Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

14 16 18 20 22 24 26 28 30 30 31 31 0 6 25 30 32 32 19.180 21.560 24.360 26.990 29.470 32.860 35.990 38.060 40.610 2.01 1.71 2.02 1.89 1.79 2.44 2.25 1.49 1.84 6.59 5.62 6.61 6.21 5.86 8.01 7.39 4.89 6.02

32.12 34 36 38 40 42 44 46 48 50 52 55.02 58 60 62 64 66 68 70 72 74 76 78 80 82 84 86 88 90 0 10 33 37.5 37.5 37.5 37.5 0 12 33 37.5 37.5 0 30 37.5 37.5 37.5 37.5 0 35 39 39 39 39 0 32 40 40 40 44.210 47.210 51.420 54.480 57.110 60.110 63.930 66.880 69.210 73.850 77.210 82.620 87.670 91.870 95.630 98.870 101.690 105.690 109.260 114.200 117.050 119.710 123.560 127.080 130.950 134.790 138.780 141.650 145.010 2.45 2.30 3.03 2.20 1.89 2.16 2.75 2.12 1.68 3.34 2.42 2.58 2.44 3.02 2.71 2.33 2.03 2.88 2.57 3.56 2.05 1.92 2.77 2.53 2.79 2.76 2.87 2.07 2.42 8.02 7.54 9.94 7.23 6.21 7.09 9.02 6.97 5.50 10.96 7.94 8.46 8.01 9.92 8.88 7.65 6.66 9.45 8.43 11.67 6.73 6.28 9.09 8.31 9.14 9.07 9.43 6.78 7.94

A-41

Appendix: Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Critical flux 75% Car wash wastewater (intermittent mode) (Phase 4)

Time (min) TMP (KPa) Volume collected in (mL) Flow (L/d) Flux (L/m2.h)

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 32 32 0 2 25 31 35 35 35 0 25 32.5 34 34 34 0.00 1.78 3.49 5.60 6.84 8.68 10.91 13.31 15.69 17.67 19.08 20.30 21.59 22.86 24.58 26.74 0.00 1.28 1.23 1.52 0.89 1.32 1.61 1.73 1.71 1.43 1.02 0.88 0.93 0.91 1.24 1.56 0.00 4.20 4.04 4.98 2.93 4.35 5.27 5.67 5.62 4.68 3.33 2.88 3.05 3.00 4.06 5.10

32.35 34 36 38 40 42 44.2 46 48 50 52 54 56 58 60 62 64 66 68 70 72 74 0 32 37 37 37 37 0 26 37 37 37 37 0 26 37 37 39 39 0 25 40 40 29.40 31.36 35.32 38.49 42.08 45.37 48.44 51.33 55.82 60.02 63.20 65.82 68.53 71.55 75.98 78.05 80.26 83.15 85.50 87.88 93.42 94.68 1.63 1.71 2.85 2.28 2.58 2.37 2.01 2.31 3.23 3.02 2.29 1.89 1.95 2.06 3.19 1.49 1.59 2.08 1.69 1.71 3.99 0.91 5.35 5.61 9.35 7.49 8.48 7.77 6.59 7.59 10.61 9.92 7.51 6.19 6.40 6.77 10.46 4.89 5.22 6.83 5.55 5.62 13.09 2.98

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Appendix: Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

76 78 80 82 84 86 88 90 40 40 0 18 39 40 40 40 96.82 99.04 101.70 104.08 108.68 110.62 113.89 115.97 1.54 1.60 1.92 1.71 3.31 1.40 2.35 1.50 5.06 5.24 6.28 5.62 10.87 4.58 7.72 4.91

Critical flux 100% Car wash wastewater (intermittent mode) (Phase 5)

TMP (KPa) Flow (L/h) Flux(L/m2.h) Time (min) Volume collected in (mL)

0 2 4 6 8 10 12 14.2 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 0 18 22 22 22 22 0 16 22 22 22 22 0 15 22 25 27 30 0 20 30 30 30 30 0 20 28 28 25 25 0 1.14 3.40 5.11 6.51 7.49 8.01 9.03 11.94 14.03 15.33 15.99 16.65 17.53 19.68 21.64 23.81 25.31 28.14 28.68 32.71 34.42 35.51 36.24 37.47 39.11 42.32 44.85 46.55 47.51 0.03 0.03 0.07 0.05 0.04 0.03 0.02 0.03 0.10 0.06 0.04 0.02 0.02 0.03 0.06 0.06 0.07 0.05 0.08 0.02 0.12 0.05 0.03 0.02 0.04 0.05 0.10 0.08 0.05 0.03 0 2.69 5.34 4.04 3.31 2.31 1.23 2.19 7.64 4.94 3.07 1.56 1.56 2.08 5.08 4.63 5.13 3.54 6.69 1.28 9.52 4.04 2.57 1.72 2.91 3.87 7.58 5.98 4.02 2.27

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Appendix: Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

60 62 64 66 68 70 72 74 76 78 80 82 84 86 88 90 0 12 18 39 40 40 0 20 32 40 40 40 40 0 35 40 2.24 2.57 6.76 6.64 5.01 3.31 4.42 7.37 5.57 8.72 4.94 4.25 5.39 4.70 9.14 11.46 48.46 49.55 52.41 55.22 57.34 58.74 60.61 63.73 66.09 69.78 71.87 73.67 75.95 77.94 81.81 86.66 0.03 0.03 0.09 0.08 0.06 0.04 0.06 0.09 0.07 0.11 0.06 0.05 0.07 0.06 0.12 0.15

Critical flux 100% Car wash wastewater (After reducing HRT) (intermittent mode) (Phase 6)

Time (min) TMP (KPa) Volume collected in (mL) Flow (L/h) Flux (L/m2.h)

0 2 4 6 8 10 12.2 14.26 16 18 20 22 24 26 28 30 32 34 36 40 42 44.2 30 40 42 47 0 30 40 45 48 0 38 42 45 0 20 40 46 49 0 42 49 50 0.00 3.21 6.44 9.78 13.07 16.75 19.73 23.01 26.38 29.63 33.04 36.16 39.39 42.96 46.09 49.39 52.41 55.62 59.06 65.55 68.82 72.43 0.00 0.10 0.10 0.10 0.10 0.11 0.08 0.10 0.12 0.10 0.10 0.09 0.10 0.11 0.09 0.10 0.09 0.10 0.10 0.10 0.10 0.10 0.00 7.58 7.63 7.89 7.77 8.69 6.40 7.52 9.15 7.68 8.06 7.37 7.63 8.43 7.39 7.80 7.13 7.58 8.13 7.67 7.72 7.75

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Appendix: Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

46 48 50 52 54 56 58 60 0 40 48 50 0 25 40 48 76.02 79.21 82.43 86.28 89.39 92.89 96.34 99.63 0.12 0.10 0.10 0.12 0.09 0.11 0.10 0.10 9.42 7.54 7.61 9.09 7.35 8.27 8.15 7.77

62 64 67.08 68 70 72 74 76 78 80 82 84 86 88 90 51 0 30 45 50 52 0 42 48 50 52 0 40 50 50 103.15 107.27 110.34 112.72 115.19 117.87 120.65 123.78 126.22 129.03 132.11 135.22 139.07 141.87 144.95 0.11 0.12 0.06 0.16 0.07 0.08 0.08 0.09 0.07 0.08 0.09 0.09 0.12 0.08 0.09 8.31 9.73 4.71 12.22 5.83 6.33 6.57 7.39 5.76 6.64 7.28 7.35 9.09 6.61 7.28

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Appendix: Application of Ceramic Ultrafiltration/Reverse Osmosis Membranes and Enhanced Membrane Bioreactor for the Reuse of Car Wash Wastewater

Picture of Enhanced Membrane Bioreactor (eMBR) setup

Fouling of membrane module

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Page 2 of 3

17-15561

617889

RMIT University

Page: Batch No: Report Number: Client: Client Program Ref:

Shamima Moazzem

MBAS

Oil & Grease

Analysis:

Chemistry

Sample Sampled Date Your Ref

O & G mg/L

Component: Units: Sample Type

MBAS, as LAS MW342 mg/L 83

<0.05

5146844 26-03-17 1,3,5 Carwash WW 5146846 27-03-17 2,9,6,8 Permeate

WATER WATER

PAH

Analysis:

PAH

Sample Sampled Date Your Ref

NAP mg/L

Acenaphthylene mg/L

ACE mg/L

FLU mg/L

PHE mg/L

ANT mg/L

FLA mg/L

BAA mg/L

PYR mg/L

Component: Units: Sample Type

<0.001

5146844 26-03-17 1,3,5 Carwash WW 5146846 27-03-17 2,9,6,8 Permeate

WATER WATER

PAH

Analysis:

PAH

Sample Sampled Date Your Ref

CHR mg/L

BBF mg/L

BKF mg/L

BAP mg/L

DBA mg/L

BGP mg/L

IPY mg/L

TOTPAH mg/L

Component: Units: Sample Type

<0.001

5146844 26-03-17 1,3,5 Carwash WW 5146846 27-03-17 2,9,6,8 Permeate

WATER WATER

PCBs

Analysis:

PCBs

Sample Sampled Date Your Ref

Total PCBs mg/L

Aroclor 1016 mg/L

Aroclor 1221 mg/L

Aroclor 1232 mg/L

Aroclor 1242 mg/L

Aroclor 1248 mg/L

Aroclor 1254 mg/L

Aroclor 1260 mg/L

Component: Units: Sample Type

<0.001

5146844 26-03-17 1,3,5 Carwash WW 5146846 27-03-17 2,9,6,8 Permeate

WATER WATER

Colilert (2000)

Analysis:

Microbiology

Sample Sampled Date Your Ref

E.coli orgs/100mL

Component: Units: Sample Type

4900

5146845 27-03-17 7 Carwash 5146846 27-03-17 2,9,6,8 Permeate

WATER WATER

Samples not collected by ALS and are tested as received.

A blank space indicates no test performed. Soil results expressed in mg/kg dry weight unless specified otherwise. Soil microbiological testing was commenced within 48 hours from the day received unless otherwise stated. Water microbiological testing was commenced on the day received and within 24 hours of sampling unless otherwise stated. MM524: Plate count results <10 per mL and >300 per mL are deemed as approximate. MM526: Plate count results <2,500 per mL and >250,000 per mL are deemed as approximate. Calculated results are based on raw data.

Page 3 of 3

17-15561

617889

RMIT University

Page: Batch No: Report Number: Client: Client Program Ref:

Shamima Moazzem

Samples not collected by ALS and are tested as received.

Measurement Details

Sample Name Average of 'Carwash Waste water 2'

Measurement Date Time 21/03/2016 2:01:19 PM

Operator Name e61822

Analysis Date Time 21/03/2016 2:01:19 PM

SOP File Name HydroLV.cfg

Result Source Averaged

Analysis

Particle Name Silica (RI 1.544, AI 0.0)

Particle Refractive Index 1.544

Dispersant Name Water

Dispersant Refractive Index 1.330

Particle Absorption Index 0.000

Laser Obscuration 4.67 %

Weighted Residual 0.70 %

Scattering Model Mie

Analysis Model General Purpose

Analysis Sensitivity Normal

Result

Concentration 0.0057 %

Span 2.188

Uniformity 0.787

Result Units Volume

Specific Surface Area 613.1 m²/kg

Dv (10) 5.18 µm

D [3,2] 9.79 µm

Dv (50) 11.4 µm

D [4,3] 16.3 µm

Dv (90) 30.1 µm

Frequency (compatible)

10.0

8.0

)

6.0

4.0

( y t i s n e D e m u o V

2.0

0.0

0.01

0.1

1.0

10.0

100.0

1,000.0

10,000.0

Size Classes (µm)

[55] Average of 'Carwash Waste water 2'-21/03/2016 2:01:19 PM

Size (µm) % Volume In

0.00

0.98

4.21

0.10

0.0679

0.460

3.12

21.2

144

976

0.0100

0.00

1.84

3.42

0.00

0.0771

0.523

3.55

24.1

163

1110

0.0114

0.00

2.87

2.68

0.00

0.0876

0.594

4.03

27.4

186

1260

0.0129

0.00

3.95

2.03

0.00

0.0995

0.675

4.58

31.1

211

1430

0.0147

0.00

4.94

1.50

0.00

0.113

0.767

5.21

35.3

240

1630

0.0167

0.00

5.80

1.11

0.00

0.128

0.872

5.92

40.1

272

1850

0.0189

0.00

6.50

0.85

0.00

0.146

0.991

6.72

45.6

310

2100

0.0215

0.00

7.01

0.69

0.00

0.166

1.13

7.64

51.8

352

2390

0.0244

0.00

7.31

0.60

0.00

0.188

1.28

8.68

58.9

400

2710

0.0278

0.00

7.39

0.55

0.00

0.214

1.45

9.86

66.9

454

3080

0.0315

0.00

7.25

0.51

0.00

0.243

1.65

11.2

76.0

516

3500

0.0358

0.00

6.91

0.46

0.00

0.276

1.88

12.7

86.4

586

0.0407

0.00

6.40

0.40

0.00

0.314

2.13

14.5

98.1

666

0.0463

0.00

0.10

5.75

0.31

0.00

0.357

2.42

16.4

111

756

0.0526

0.00

0.40

5.00

0.21

0.00

0.405

2.75

18.7

127

859

0.0597

Malvern Instruments

Analysis

Measurement Details

Operator Name e61822

Analysis Date Time 9/03/2017 10:09:14 AM

Sample Name Average of 'carwash 5

Measurement Date Time 9/03/2017 10:09:14 AM

Result Source Averaged

SOP File Name HydroLV.cfg

Analysis

Result

Particle Name Silica (RI 1.544, AI 0.01)

Concentration 0.0030 %

Particle Refractive Index 1.544

Span 3.313

Particle Absorption Index 0.010

Uniformity 2.514

Dispersant Name Water

Specific Surface Area 345.3 m²/kg

Dispersant Refractive Index 1.330

D [3,2] 17.4 µm

Scattering Model Mie

D [4,3] 159 µm

Analysis Model General Purpose

Dv (10) 7.21 µm

Weighted Residual 0.34 %

Dv (50) 54.8 µm

Laser Obscuration 1.38 %

Dv (90) 189 µm

Frequency (compatible)

)

( y t i s n e D e m u o V

0.01

0.1

1.0

10.0

100.0

1,000.0

10,000.0

Size Classes (µm)

[132] Average of 'carwash 5 '-9/03/2017 10:09:14 AM

Result

Size (µm)

% Volume In

Size (µm)

% Volume In

Size (µm)

% Volume In

Size (µm)

% Volume In

Size (µm)

% Volume In

Size (µm)

% Volume In

Size (µm)

% Volume In

Size (µm)

% Volume In

0.0100

0.00

0.0597

0.00

0.357

0.00

2.13

0.40

12.7

2.42

76.0

4.47

454

0.00

2710

0.41

0.0114

0.00

0.0679

0.00

0.405

0.00

2.42

0.51

14.5

2.60

86.4

4.80

516

0.00

3080

0.21

0.0129

0.00

0.0771

0.00

0.460

0.00

2.75

0.61

16.4

2.74

98.1

4.92

586

0.00

3500

0.0147

0.00

0.0876

0.00

0.523

0.06

3.12

0.72

18.7

2.84

111

4.80

666

0.00

0.0167

0.00

0.0995

0.00

0.594

0.10

3.55

0.85

21.2

2.88

127

4.43

756

0.00

0.0189

0.00

0.113

0.00

0.675

0.11

4.03

0.99

24.1

2.85

144

3.84

859

0.00

0.0215

0.00

0.128

0.00

0.767

0.10

4.58

1.14

27.4

2.78

163

3.11

976

0.10

0.0244

0.00

0.146

0.00

0.872

0.08

5.21

1.28

31.1

2.70

186

2.33

1110

0.23

0.0278

0.00

0.166

0.00

0.991

0.04

5.92

1.43

35.3

2.65

211

1.61

1260

0.40

0.0315

0.00

0.188

0.00

1.13

0.02

6.72

1.57

40.1

2.69

240

1.00

1430

0.56

0.0358

0.00

0.214

0.00

1.28

0.05

7.64

1.73

45.6

2.85

272

0.54

1630

0.68

0.0407

0.00

0.243

0.00

1.45

0.13

8.68

1.89

51.8

3.14

310

0.23

1850

0.73

0.0463

0.00

0.276

0.00

1.65

0.21

9.86

2.06

58.9

3.55

352

0.00

2100

0.69

0.0526

0.00

0.314

0.00

1.88

0.30

11.2

2.24

66.9

4.02

400

0.00

2390

0.58

CAR WASH WATER

Malvern Instruments Ltd.

Mastersizer - v3.62

Created: 1/01/2015

www.malvern.com

Page 1 of 1

Printed: 9/03/2017 10:14 AM

Measurement Details

14/12/2016 11:25:18 AM

Sample Name

Measurement Date Time

Average of 'raw car wash water with soap '

Operator Name e61822

Analysis Date Time 14/12/2016 11:25:18 AM

SOP File Name HydroLV.cfg

Result Source Averaged

Analysis

Particle Name Silica (RI 1.544, AI 0.01)

Particle Refractive Index 1.544

Dispersant Name Water

Dispersant Refractive Index 1.330

Particle Absorption Index 0.010

Laser Obscuration 1.23 %

Weighted Residual 1.63 %

Scattering Model Mie

Analysis Model General Purpose

Analysis Sensitivity Normal

Result

Concentration 0.0025 %

Span 15.082

Uniformity 4.973

Result Units Volume

Specific Surface Area 29380 m²/kg

Dv (10) 0.0548 μm

D [3,2] 0.204 μm

Dv (50) 152 μm

D [4,3] 793 μm

Dv (90) 2300 μm

Frequency (compatible)

8.0

6.0

)

4.0

( y t i s n e D e m u o V

2.0

0.0

0.10

1.0

10.0

100.0

1,000.0

10,000.0

0.01

Size Classes (μm)

[115] Average of 'raw car wash water with soap '-14/12/2016 11:25:18 AM

Size (μm) % Volume In

0.13

1.07

0.12

0.36

0.47

2.40

1.92

0.0679

0.460

3.12

21.2

144

976

0.0100

0.26

1.03

0.15

0.38

0.53

2.18

2.96

0.0771

0.523

3.55

24.1

163

1110

0.0114

0.39

0.98

0.19

0.41

0.59

1.86

4.03

0.0876

0.594

4.03

27.4

186

1260

0.0129

0.51

0.91

0.24

0.43

0.64

1.48

4.92

0.0995

0.675

4.58

31.1

211

1430

0.0147

0.62

0.83

0.28

0.43

0.69

1.08

5.45

0.113

0.767

5.21

35.3

240

1630

0.0167

0.72

0.75

0.31

0.41

0.75

0.71

5.49

0.128

0.872

5.92

40.1

272

1850

0.0189

0.82

0.66

0.32

0.38

0.85

0.42

5.03

0.146

0.991

6.72

45.6

310

2100

0.0215

0.90

0.56

0.31

0.35

1.00

0.23

4.11

0.166

1.13

7.64

51.8

352

2390

0.0244

0.97

0.47

0.30

0.31

1.20

0.13

2.88

0.188

1.28

8.68

58.9

400

2710

0.0278

1.03

0.37

0.30

0.29

1.45

0.10

1.48

0.214

1.45

9.86

66.9

454

3080

0.0315

1.07

0.29

0.30

0.27

1.73

0.11

0.243

1.65

11.2

76.0

516

3500

0.0358

1.10

0.22

0.31

0.28

2.02

0.17

0.276

1.88

12.7

86.4

586

0.0407

1.12

0.16

0.32

0.30

2.26

0.28

0.314

2.13

14.5

98.1

666

0.0463

1.12

0.13

0.33

0.35

2.43

0.54

0.357

2.42

16.4

111

756

0.0526

1.10

0.12

0.34

0.40

2.48

1.09

0.405

2.75

18.7

127

859

0.0597

Software Version: 2.20 Malvern Instruments Ltd - www.malvern.com Page 1 of 1

Measurement Details

25/07/2016 2:18:53 PM

Sample Name

Measurement Date Time

Average of 'Carwash Waste water Sample 3 150716'

Operator Name e61822

Analysis Date Time 25/07/2016 2:18:53 PM

SOP File Name HydroLV.cfg

Result Source Averaged

Analysis

Particle Name Silica (RI 1.544, AI 0.01)

Particle Refractive Index 1.544

Dispersant Name Water

Dispersant Refractive Index 1.330

Particle Absorption Index 0.010

Laser Obscuration 2.52 %

Weighted Residual 1.25 %

Scattering Model Mie

Analysis Model General Purpose

Analysis Sensitivity Normal

Result

Concentration 0.0014 %

Span 35.667

Uniformity 9.282

Result Units Volume

Specific Surface Area 19420 m²/kg

Dv (10) 0.0942 µm

D [3,2] 0.309 µm

Dv (50) 3.35 µm

D [4,3] 32.0 µm

Dv (90) 120 µm

Frequency (compatible)

5.0

4.0

)

3.0

2.0

( y t i s n e D e m u o V

1.0

0.0

0.01

0.1

1.0

10.0

100.0

1,000.0

10,000.0

Size Classes (µm)

[79] Average of 'Carwash Waste water Sample 3 150716'-25/07/2016 2:18:53 PM

Size (µm) % Volume In

0.00

1.48

0.81

3.49

0.24

1.14

0.03

0.0679

0.460

3.12

21.2

144

976

0.0100

0.00

1.65

0.69

3.85

0.27

1.26

0.02

0.0771

0.523

3.55

24.1

163

1110

0.0114

0.00

1.80

0.61

4.09

0.34

1.26

0.00

0.0876

0.594

4.03

27.4

186

1260

0.0129

0.00

1.92

0.56

4.16

0.45

1.16

0.00

0.0995

0.675

4.58

31.1

211

1430

0.0147

0.00

2.00

0.53

4.03

0.56

0.98

0.00

0.113

0.767

5.21

35.3

240

1630

0.0167

0.05

2.05

0.51

3.72

0.65

0.76

0.00

0.128

0.872

5.92

40.1

272

1850

0.0189

0.13

2.05

0.51

3.26

0.66

0.55

0.00

0.146

0.991

6.72

45.6

310

2100

0.0215

0.21

2.01

0.55

2.72

0.59

0.36

0.00

0.166

1.13

7.64

51.8

352

2390

0.0244

0.32

1.93

0.66

2.16

0.45

0.33

0.00

0.188

1.28

8.68

58.9

400

2710

0.0278

0.44

1.81

0.89

1.62

0.30

0.29

0.00

0.214

1.45

9.86

66.9

454

3080

0.0315

0.59

1.66

1.23

1.16

0.20

0.24

0.243

1.65

11.2

76.0

516

3500

0.0358

0.75

1.49

1.65

0.79

0.23

0.18

0.276

1.88

12.7

86.4

586

0.0407

0.93

1.30

2.12

0.53

0.40

0.12

0.314

2.13

14.5

98.1

666

0.0463

1.12

2.60

0.36

0.66

0.06

0.357

2.42

16.4

111

756

0.0526

1.30

0.95

3.06

0.27

0.93

0.04

0.405

2.75

18.7

127

859

0.0597

Measurement Details

22/11/2016 1:47:10 PM

Sample Name

Measurement Date Time

Average of 'Permeate after Coagulation '

Operator Name e61822

Analysis Date Time 22/11/2016 1:47:10 PM

SOP File Name HydroLV.cfg

Result Source Averaged

Analysis

Particle Name Silica (RI 1.544, AI 0.01)

Particle Refractive Index 1.544

Dispersant Name Water

Dispersant Refractive Index 1.330

Particle Absorption Index 0.010

Laser Obscuration 1.43 %

Weighted Residual 0.38 %

Scattering Model Mie

Analysis Model General Purpose

Analysis Sensitivity Normal

Result

Concentration 0.0068 %

Span 32.882

Uniformity 6.964

Result Units Volume

Specific Surface Area 181.2 m²/kg

Dv (10) 16.2 µm

D [3,2] 33.1 µm

Dv (50) 45.9 µm

D [4,3] 345 µm

Dv (90) 1530 µm

Frequency (compatible)

8.0

6.0

)

4.0

( y t i s n e D e m u o V

2.0

0.0

0.1

1.0

10.0

100.0

1,000.0

10,000.0

0.01

Size Classes (µm)

[102] Average of 'Permeate after Coagulation '-22/11/2016 1:47:10 PM

Size (µm) % Volume In

0.00

0.15

4.75

1.02

0.71

0.0679

0.460

3.12

21.2

144

976

0.0100

0.00

0.14

5.22

1.14

1.10

0.0771

0.523

3.55

24.1

163

1110

0.0114

0.00

0.14

5.52

1.31

1.51

0.0876

0.594

4.03

27.4

186

1260

0.0129

0.00

0.14

5.62

1.46

1.84

0.0995

0.675

4.58

31.1

211

1430

0.0147

0.00

0.15

5.50

1.54

2.03

0.113

0.767

5.21

35.3

240

1630

0.0167

0.00

0.20

5.19

1.53

2.04

0.128

0.872

5.92

40.1

272

1850

0.0189

0.00

0.29

4.73

1.39

1.86

0.146

0.991

6.72

45.6

310

2100

0.0215

0.00

0.45

4.15

1.15

1.52

0.166

1.13

7.64

51.8

352

2390

0.0244

0.00

0.70

3.52

0.86

1.07

0.188

1.28

8.68

58.9

400

2710

0.0278

0.00

1.06

2.87

0.57

0.55

0.214

1.45

9.86

66.9

454

3080

0.0315

0.00

0.04

1.53

2.26

0.32

0.243

1.65

11.2

76.0

516

3500

0.0358

0.00

0.09

2.10

1.74

0.19

0.276

1.88

12.7

86.4

586

0.0407

0.00

0.13

2.76

1.35

0.17

0.314

2.13

14.5

98.1

666

0.0463

0.00

0.15

3.46

1.10

0.22

0.357

2.42

16.4

111

756

0.0526

0.00

0.15

4.14

1.00

0.40

0.405

2.75

18.7

127

859

0.0597

Measurement Details

22/11/2016 2:03:39 PM

Sample Name

Measurement Date Time

Average of 'Permeate after Sand Filtration average '

Operator Name e61822

Analysis Date Time 22/11/2016 2:03:39 PM

SOP File Name HydroLV.cfg

Result Source Averaged

Analysis

Particle Name Silica (RI 1.544, AI 0.01)

Particle Refractive Index 1.544

Dispersant Name Water

Dispersant Refractive Index 1.330

Particle Absorption Index 0.010

Laser Obscuration 0.64 %

Weighted Residual 1.33 %

Scattering Model Mie

Analysis Model General Purpose

Analysis Sensitivity Normal

Result

Concentration 0.0024 %

Span 54.542

Uniformity 10.672

Result Units Volume

Specific Surface Area 4015 m²/kg

Dv (10) 0.487 μm

D [3,2] 1.49 μm

Dv (50) 29.2 μm

D [4,3] 323 μm

Dv (90) 1590 μm

Frequency (compatible)

6.0

)

4.0

2.0

( y t i s n e D e m u o V

0.0

0.10

1.0

10.0

100.0

1,000.0

10,000.0

0.01

Size Classes (μm)

[121] Average of 'Permeate after Sand Filtration average '-22/11/2016 2:03:39 PM

Size (μm) % Volume In

0.00

0.19

0.74

0.53

4.32

0.24

0.73

0.0679

0.460

3.12

21.2

144

976

0.0100

0.00

0.27

0.71

0.58

4.65

0.20

1.17

0.0771

0.523

3.55

24.1

163

1110

0.0114

0.00

0.35

0.68

0.65

4.79

0.20

1.62

0.0876

0.594

4.03

27.4

186

1260

0.0129

0.00

0.44

0.65

0.70

4.75

0.19

1.99

0.0995

0.675

4.58

31.1

211

1430

0.0147

0.00

0.53

0.61

0.72

4.54

0.18

2.20

0.113

0.767

5.21

35.3

240

1630

0.0167

0.00

0.61

0.55

0.72

4.35

0.15

2.20

0.128

0.872

5.92

40.1

272

1850

0.0189

0.00

0.68

0.49

0.73

3.97

0.11

1.99

0.146

0.991

6.72

45.6

310

2100

0.0215

0.00

0.74

0.43

0.79

3.45

0.05

1.61

0.166

1.13

7.64

51.8

352

2390

0.0244

0.00

0.78

0.40

0.93

2.84

0.02

1.12

0.188

1.28

8.68

58.9

400

2710

0.0278

0.00

0.81

0.39

1.18

2.22

0.01

0.57

0.214

1.45

9.86

66.9

454

3080

0.0315

0.00

0.83

0.41

1.56

1.63

0.02

0.243

1.65

11.2

76.0

516

3500

0.0358

0.01

0.83

0.48

2.05

1.14

0.04

0.276

1.88

12.7

86.4

586

0.0407

0.03

0.81

0.50

2.63

0.75

0.08

0.314

2.13

14.5

98.1

666

0.0463

0.07

0.79

0.49

3.25

0.48

0.17

0.357

2.42

16.4

111

756

0.0526

0.12

0.76

0.50

3.84

0.31

0.38

0.405

2.75

18.7

127

859

0.0597

Software Version: 2.20 Malvern Instruments Ltd - www.malvern.com Page 1 of 1