Doctoral thesis abstract: Studying the capability of greywater treatment on site by using laterite material

MINISTRY OF EDUCATION AND TRAINING MINISTRY OF AGRICULTURE AND RURAL DEVELOPMENT

WATER RESOURCES UNIVERSITY KHUONG THI HAI YEN STUDYING THE CAPABILITY OF GREYWATER TREATMENT ON SITE BY USING LATERITE MATERIAL

Major: Water resources engineering Code: 62580212

DOCTORAL THESIS ABSTRACT HANOI, 2016

The research is completed in Water Resources University, Hanoi, Vietnam

Advisor 1: Assoc. Prof., Dr. PHAM Thi Minh Thu Advisor 2: Assoc. Prof., Dr. NGUYEN Thi Kim Cuc

Reviewer 1: Dr. TRINH Xuan Lai, Vietnam Water Suply and Sewerage Association Reviewer 2: Assoc. Prof., Dr. NGUYEN Ngoc Dung, Ministry of Construction Reviewer 3: Prof., Dr. TRAN Huu Uyen, Expert of Water Treatment

The doctoral thesis has been presented at Water Resources University, Hanoi, Vietnam At 8.30 on 30 th October 2016

Finding the doctoral thesis in: - National Library - Library of Water Resources University

INTRODUCTION

1. Urgency of research:

Greywater accounts for 69%1 of domestic wastewater flow and contaminant concentrations lower than the blackwater but most of the pollution parameters are not meet up the Regulation to discharge directly into the environment. Wastewater treatment technology such as SBR, A2O only effective in treatment of organic matter but not effective in treatment of nitrogen to reach the require level; and often apply to big wastewater treatment plants. Need to research a suitable processing solution with the scale and characteristics of greywater as the criteria for: simple operation, high nitrogen removal efficiency, area of land occupied is less and towards sustainable technologies.

Laterite is local materials, available in many areas in Vietnam country. Laterite is form structure, contains many kinds of minerals such as clay (kaolinite, bentonite), the hydroxides of iron, the hydroxides aluminum, zeolite, brucite, gibbsite, goethite2 ... are substances that the polarity inside the water, with the ability to exchange ions, in the crystal structure, manies void and large specific surface area. Therefore the laterite is easy to join the adsorption, ion exchange, electrostatically with some pollution matter and having the potential of wastewater treatment field. However, these ability is reduced with time, together with the clog process because the developed of microbial membranes. This problem can improve with using laterite according multilayer soil layering engineering3.

Thesis "Studying the capability of greywater treatment on site by using laterite material" was conducted to determine the ability to treat the greywater of laterite with multilayer layering engineering. The success of the studing is opened up a new direction in the use of local materials, environmentally friendly to treat greywater on-site; contribute to reduce pressure on the

1 Barnes, D và cộng sự, Water and Wastewater Engineering Systems, Pitman Books Ltd., ed. London, 1981. 2 Nyle C.Brandy, The nature and the Properties of soils, 2nd ed.: ISBN: 9780130167637, 2001. 3 T.Masunaga et al, "Characteristics of wastewater treatment using a Multi Soil Layering system in relation to wastewater contamination level and hydrolic loading rates," Soil Science and Plant Nutrition, pp. 123-125, 2007.

wastewater treatment plants, the length of urban pipelines and environmental pollution. The treated of greywater can be used for irrigation, control the distribution domestic buildings and saving water resources for the future.

1.1 The aim of research

Determination of greywater characteristics from some buildings in Hanoi city;

Explaination of the principle of removing the main pollutants out of greywater

by using laterite with multi soil layering engineering; Determination of + -N. The number of decomposition rate coefficients of BOD5, COD and NH4

laterite layer is calculated based on these coefficients; Successful greywater

treatment from building by using laterite with Multi Soil Layering engineering

and the treated effluent meet up the National Regulations (QCVN

14:2008/BTNMT; QCVN 08-MT:2015/BTNMT).

1.2 Object and scope of research

1.2.1 Object of research

Multi Soil Layering engineering is using laterite as main material for greywater

treatment from buliding in Ha noi city.

1.2.2 Scope of research

Greywater from some buildings in Hanoi city; Multi Soil Layering engineering

with natural laterite and heat denaturation laterite.

1.3 Method of research

Using main method of research such as: investigation and sample collection,

inheritance, lab analysis, lab model, pilot model, statistical method.

1.4 Content of research

Determination of greywater characteristics from some buildings in Hanoi city;

Studying the capacibilityof greywater treatment through lab Multi Soil

Layering models; Application the lab result for designing the pilot (MSL6-PL)

for greywater treatment onsite from B5-Yen Thuong building.

1.5 The scientific and practical significances

+ -N and

1.5.1 Scientific significances

- Determination of decomposition rate coefficients of BOD5, NH4 COD. The number of laterite layer is calculated based on these coefficients.

- Determination of efficiency, explaination of the principle of removing the main pollutants out of greywater by using laterite with multi soil layering engineering;

1.5.2 Practical significances

Applying for greywater treatment from buildings in Hanoi city. The quality of

effluent meet up the National Regulation QCVN 14:2008/BTNMT; QCVN

08:2008/BTNMT.

1.6 The structure of the thesis

the thesis beyond

The structure of the preamble; conclusions and recommendations; lists of articles were published; reference section; annexes; Thesis is presented in threes chapters, including:

Chapter 1. Overview of the research problems

Chapter 2. Basic of scientific, material and studying method for greywater treatment by using laterite with Multi Soil Layering Engineering.

Chapter 3. The research results of greywater treatment on-site by using laterite with Multil Soil Layering engineering.

CHAPTER 1 : OVERVIEW OF THE RESEARCH PROBLEMS

1.1 Greywater

Greywater is part of the waste water without treatment and collected from showers, lavabol, tub, kitchen sink… (except toilet and urine sink) and accounted for 69% of domestic wastewater. The pollution concentrations of organics and nutiens such as BOD5, COD, N, P are lower than the concentration of black wastewater. The pollution concentrations in greywater depends on habit and level of living, traditional, economic conditions, management, methods of greywater collection and source of drainage etc each area.

Greywater is treated by chemical – physical, biological, mechanical method.

These are many researchs of greywater in the world, the greywater is treated to seek of resources water saving in future or reducing of environmental pollution. Some case studies such as M. Halalsheh, 2008 (Jordan); Peter L.M. Veneman and Bonnie Stewart, 2002 (USA); Elmitwalli et al, 2000 (Netherlands). In Vietnam, Stefania Paris and Celine Schlapp, 2010; N.V.Anh et al, 2012; K.T.H. Yen et al, 2014 studies greywater, the results show that most of the contaminants concentrations exceed the allowable value specified in the QCVN14: 2008/BTNMT. Therefore, the greywater are required to treat before being discharged into the environment.

1.2 Laterite and Application for wastewater treatment.

1.2.1 Useful minerals for contaminant treatment in greywater

These the mineralogy of laterite are clay (kaolinite, bentonite), the hydroxides

of iron, alumina, zeolite, diatomite, and has been characterized by the topology

of the form -O-H H-O-H-O loose. Group OH- ions easily combined with

oppositely in retail gas oxygen atoms in this link may be involved in the

process of cellular respiration of the microorganism; the basic structural unit

consisting of a tetrahedron made of Si and O, the octahedral blocks from OH- and metal cations Al3+, Fe3+. Al3+ ions, Fe3+ is likely linked to the opposite ion is the glue sound in wastewater4.

1.2.2 The reseaches of laterite applycation in wastewater treatment field

These are a lot of researches which using laterite as absortion material for wastewater treatment. Such as R. B. Wood and C. F. Mc Atamne, 1996 (USA); Avinash M et al, (India); Mitali Sarkar et al, 2006 (India); Saynor MJ & Harford, 2010 (USA); Yu Xiaohong et al, 2009 (China); Felix Udoeyo et al, 2010 (USA); Liang Zhang et al, 2011 (China); I.M.M Ranhman et al, 2008 (Japan). In Vietnam, Nguyen Thi Hang Nga, 2014; Tran Hong Con, 2010; Dang Duc Truyen, 2011 research on laterite and heat denaturation to made filter material for water treatment. The result show that laterite can treat the fluoride,

4 Đỗ Thị Vân Thanh, "Laterit - đá ong hóa và sự thoái hóa đất của một số tỉnh vùng đồi Trung du miền Bắc Việt Nam," 1995

heavy metal with high performance; the organics concentration is reduced but creating of residues, it’s the cause to make flog inside the multi soil layering system. Most of researches processed inside the laboratories with assuming pollution matter then different distance when application in real.

1.3 Multi Soil Layering

Influent

Soil units: These units are made from soils, complete the decomposition process of organics, nutrients base on the activities of exotic, aerobic and anerobic bateria.

Lining: Using of material such as activated carbon, zeolite, gravel for adsorption and decomposition the contaminants base on the adsorption capactity of material and activities of materia.

Effluent

Multi Soil Layering is using multi- layers of material with original from soil, arranged in a certain sequence to treat the contaminants inside wastewater. T.Matsunaga research and develop the Multi Soil Layering from the 1990s in Japan as a wastewater treatment solution with low cost (Fig 1.12).

Fig 1.12: Structural diagram of multi soil layering

In this thesis used the results of some laboratory researches, such as: With the soil unit are thick then effect to treat nitrogen but making the clog quickly; With soil unit are thin then effect to treat organics but not effective for nitrogen; With the soil units are thickness and narrow then the perfomance of contaminants are average but can work well with high hydraulic loading, less clog and the hydraulic retention time inside the multi soil layering is inversely related to the hydraulic loading5. The pollution levels of contaminants inside wastewater input less effection to treatment performance of suspended solid, organics and nitrogen but more effective to phosphorus; Hydraulic loading is is inversely related to performance of phosphorous; The arrangement of the

5 Sato K., Masunaga T., Inada K., Tanaka T., Arai Y., Unno S. and Wakatsuki T., "The development of high speed treatment of polluted river water by the multi-soil-layering method, Examination of various materials and structure," .Jpn J. Soil Sci. Plant Nutr., vol. 200, 2005.

material structure is meaningful and high treatment performance when hydraulic loading is less than or equal 2.000 L/m2.day. When the wastewater loading is beyond 2.000 L/m2.day then the structure arrangement of material is not effective much to the treatment performance6. Until now, there is not any research of application the multi soil layering engineering in Vietnam.

CHAPTER 2 : BASIC OF SCIENTIFIC, MATERIAL AND STUDYING METHOD FOR GREYWATER TREAMENT BY USING LATERITE WITH MULTI SOIL LAYERING ENGINEERING

2.1 Basic of scientific for greywater treatment by using laterite with multi soil layering engineering

- The adsorption reaction occurs with the adsorption kinetic model. The ability

of the contaminants adsorption of laterite was evaluated using the Langmuir

equation (2-1): (2-1)

- Organics, nutrients inside the greywater are removed through the action of available microorganisms. Model of decomposition Monod is used to determine the biodegradation coefficients and is written as follows7:

(2-2)

2.2 Material

The main material are laterite with dimension LxBxH = 30x15x5 cm and heat denaturation laterite at 9500C with diameter 1-3mm.

2.3 Studying Method

2.3.1 Laboratory model

Laboratory models made of stailess steel, cube with dimension Length x Wide x High = 15x50x(33-76) cm; inside made of 3,4,5,6,7 laterite layers and the laterite unit is stagger between up and next down layers, like brick wall (MSL3,

6 Xin CHEN et al, "Effect of structural difference on wastewater treatment efficiency in Multil Soil Layering systems: Relationship between soil mixture," Soil Science and Plant Nutrition, vol. 53, p. 206–214, 2007. 7 Lawrence A.W. and McCarty P.L., "A unified basis for biologycal treatment design and operation," Journal of the Sanitary Engineering Division , American Society of Chemical Engineers, vol. 96, p. 757, 1970.

MSL4, MSL5, MSL6, MSL7); row distance is 3 cm, column distance is 2,5 cm and insertion by heat denaturation laterite with diamter 1-3 mm; the gravel is bottom of laboratory madel with diameter 4-6 cm, thickness of this support gravel is 10 cm (Fig 2.14).

Fig 2.14: Lab model of Multi Soil Layering

After removing the rubbishs, the greywater is distributed with the 2.000 littre/m2.day hydraulic loading to every laboratory models. The samples are took at influent and efflent point of every model.

2.3.2 Model of pilot

Pilot model was designed based on the coefficient ks, K; treated water meet up the value specified in QCVN 14:2008/BTMT(B) - National technical regulation

on domestic wastewater (value in domestic wastewater as being discharged into

water resources not used for the purpose of domestic water supply - with water

quality equivalent to that in column B1 of the national technical Regulation on

surface water quality) and QCVN 08-MT:2015/ BTNMT(B1) - National

Technical Regulation on surface water quality (surface water used for irrigation

purposes). After caculation then choice pilot model with 6 laterite layer (MSL6-

PL) and dimensions LxBxH = 0,95x0,5x0,68m for greywater treatment from

some apartments of the B5-Yen Thuong. MSL6-PL made of force glass, 1.2

thickness and placed in a steel frame inside with 6 natural laterite layers

arranged in staggered layers; Grades 3 cm apart and rows spaced 2.5 cm and

inserted laterite heat denaturation granular 1-3mm diameter; bottom gravel

layer 4-6 cm thick support diameter 10 cm. Gray waste water collected from the

B5-Yen Often garbage removal and lead to a 200-liter tank, then pumped into

the tissue quantification Fig with hydraulic load of 2,000 liters / m2.ngay.

Below the water sampling valve for later processing. The system is operated

continuously for 24 hours/day. Samples were taken at the beginning of the in

and out of scale Fig 10 days (Fig 2.18)

Fig 2.18: Diagram of pilot model of MSL6-PL

Notice: 1. Influent of greywater; 2. Storage tank 200littres; 3. Pump; 4. Flow meter; 5.

Weir of distribution; 6. Distribution system; 7. Laterite; 8. Heat laterite; 9. Gravels; 10.

Collection of treated; 11. Storage; 12. Pipeline; 13. Over flow; 14. Dosing equipment

2.3.3 Laboratory analysis

Samples were analyzed in the laboratory with Standard Method and equivalent

Vietnamese Standards.

2.3.4 Statistical Analysis

The results is average anlytical values plus standard deviation of all time

analytics. The relationship between laterite layers and concentration of

contaminants is expressed through the linear regression equation or logarithmic equations and assessed according to the coefficient of determination (R2).

CHAPTER 3 : THE RESEARCH RESULTS OF GREYWATER TREATMENT ON-SITE BY USING LATERITE WITH MULTI SOIL LAYERING ENGINEERING

3.1 Characteristics of greywater from buildings in Hanoi city

The results of laboratory analysis: the average concentration of contaminants inside the greywater samples which collection from some buildings (CT5B – Me Tri, 11 floor condominiums of Duc Giang, building of B5 Yen Thuong) at Table 3.1 showed that the concentration of organics, nitrogen, suspended solids total exceeded many time value which certificated in Regulation QCVN14:2008/BTNMT (B)- National technical regulation on domestic wastewater. Therefore, the greywater forced to treat before discharge into the environment.

Notice

Table 3.1: Characteristics of greywater from some building in Hanoi city Average No Paramters Unit

Meet up

-

Not meet up Not meet up

Meet up

3--P

Regulation QCVN 14:2008 (B) 5-9 - 50 100 10 -

-

- mg/L mg/L - mg/L mg/L mg/L (%) 8,13±0,12 234,10±67,2 121,87±21,24 1,97:1 258,20±29,8 2,60±0,54 4,89±0,65 52,7±5,54 pH 1 COD 2 3 BOD5 COD: BOD5 TSS 4 PO4 5 T-P 6 3--P/ T-P PO4

Meet up

+-N

NH4 T-N +-N/ T-N

mg/L mg/L (%) - 8,90±1,26 17,73±1,21 49,93 ±4,65 6,87:1 10 - 7 8 NH4 BOD5/T-N

In Vietnam, the characteristics of greywater from buildings are: the ratio COD: BOD5 = 1.97 (lower than 2 in Isarel and 4,4 in england) and suitting to use bio treatment method; the ratio BOD5:TN = 6,8 – It’s enough cacbon to occur the denification. The concentration of TN is 17,73 mg/L and higher than 13 mg/L for house in Vietnam. Amonium accounts for 49,9% for TN and phosphat accounts for 52,7% for TP of greywater. Accodding H.Henze8, this characteristic of greywater is equal dilute level.

3.2 The research results on laboratory model of Multi Soil Layering

3.2.1 The moving flow inside laboratory model

After 1st day, the total water column is reduced about 30cm, equivelent 30% total of influent flow, because water come inside the material. From 2nd da, the total water column is reduce less about 1,5% and mostly have no change from

3st day, it show that the material is saturation and the flow of effluent is stable.

Thus the reduction just occurred mainly in the first 2-3 days of water soaked

into the material and forming saturated state. The reduction of flow is

proportional to the number of laterite layers in the system.

3.2.2 The quality changing of greywater through laterite layers with multi soil layering

3.2.2.1 Organics (BOD5, COD)

The performance of BOD5 reached from 77,22% to 90,60%, the concentration of effluent reduced below 20 mg/L for greywater; The performance of BOD5 reached from 70,50% to 80,33%, the concentration of effluent reduced below

10mg/L for dilute greywater (Fig 3.3, Fig 3.4).

8 Harremoes Henze and La Cour Jansen Arvin , "Wastewater Treatment: Biological Process," 1996.

f o

)

NTNB

L / g m

(

5

Nước thải sau MSL3 Nước thải sau MSL5 Nước thải sau MSL7

Nước thải sau MSL4 Nước thải sau MSL6 Nước thải đầu vào

D O B

n o i t a r t n e c n o C

120 100 80 60 40 20 0

Fig 3.3: Concentration of BOD5 before and after treatment of greywater

f o

)

Nước thải đầu vào Nước sau MSL4 Nước sau MSL6

Nước sau MSL3 Nước sau MSL5 Nước sau MSL7

NTPL

L / g m

(

5 D O B

n o i t a r t n e c n o C

60 50 40 30 20 10 0

Fig 3.4: Concentration of BOD5 before and after treatment of dilute greywater

The performance of BOD5 BOD5 proportional to the number of laterite layers and BOD5 concentrations in influent. The concentrations of BOD5 droped fastest through 3 - 4 upper laterite layer.

200

After 6-7 laterite layers then COD concentration of effluent is stable. For the performance of COD reached 45,72%- 71,61%, COD greywater, concentration of effluent reduced below 30mg/L (Fig 3.5, Fingure 3.6).

NTNB

f o

)

160

Nước thải đầu vào Nước thải sau MSL3 Nước thải sau MSL4

120

L / g m

(

D O C

n o i t a r t n e c n o C

Fig 3.5: Concentration of COD before and after treatment of greywater

200

f o

NTPL

160

)

Nước thải đầu vào Nước thải sau MSL3 Nước thải sau MSL4

120

L / g m

(

D O C

n o i t a r t n e c n o C

Fig 3.6: Concentration of COD before and after treatment of dilute greywater

The removal process of cacbon occurs mainly in aerobic conditions, in the

process of microbial growth. The more down of laterite layer, the amount of

cacbon is reduced; the dissolved oxygen too but cacbon can link with oxigen

from O-H-O-H-O loose structure and creat the peroxite as form below:

This peroxite have a haft of active oxigen. Grace of catalase and peroxydasecan enzyme, alive cells of microorganisms resolution active peroxide and use oxygen for oxidation others persistent organics which it’s difficult to decay. Therefore, the performance of organic removal is increased.

+-N increased from 66.49% to 94.58% and The treatment performance NH4 from 79.68% to 89.91% respectively for the original greywater and dilute +-N greywater and proportional to the number of laterite layers. NH4 concentration decreased rapidly from 8.71 mg/L to 2.84 mg/L after 3rd laterite layer and to 2.19 mg/L after the 4th laterite layer; decreased slowly after the 6th, 7thlaterite layer respectively are 0.58 mg/L and 0.46 mg/L.

+-N treatment performance of dilute greywaterranged Especially the NH4 79.68% - 82.48% and of greywaterranged 66,49% and 74.16%, the treatment performance of dilute greywater is higher than performance of greywater; After 5thlaterite layer, the treatment performance has not much different but after 6th +-N treatment performance of greywateris higher than laterite layer the NH4

3.2.2.2 Nitrogen and nitrogen compounds

--N, NO2

+-N concentration of effluent is below 4 mg/L – dilute greywater. The NH4 greywater and is below 2 mg/L – dilute greywater with all laboratory models. +-N to +-N concentration decreased because: transformation from NH4 The NH4 --N (N2 can exit to sky, its’s accounting for 80-85%) and N2and NO3 +-N be adsorted bygoethite and hemathite of laterite (Fig 3.7, other part of NH4 Fig 3.8).

)

NTNB

f o

Nước thải vào Nước thải sau MSL4 Nước thải sau MSL6

Nước thải sau MSL3 Nước thải sau MSL5 Nước thải sau SML7

L / g m

(

N

- +

4 H N

n o i t a r t n e c n o C

+-N before and after treatment of greywater Fig 3.7: Concentration of NH4

)

f o

NTPL

L / g m

(

Nước thải vào Nước thải sau MSL4 Nước thải sau MSL6

Nước thải sau MSL3 Nước thải sau MSL5 Nước thải sau MSL7

N

- +

4 H N

n o i t a r t n e c n o C

+-N before and after treatment of dilute greywater

-, CO3

2-are foods for autotrophic The inorganic carbon in CO2, HCO3 - +-N to oxidized into NO3 microbiologyand effect on the transformation of NH4 (in this equation, the oxygen as electron acceptors and N as electron giving); 1g +-N need4,25 gO2 and 7.14 gCaCO3–ratio of oxygen needed for BOD NH4 oxidation is 1: 1. Grade of specical structure of laterite, 6 atom of oxygen around an atom Fe3+ and Al3+ creat the loose link of O-H-O-H-O. Therefore ion + conected with OH-, atom of oxgen can join to the oxidation of autotrophic NH4 + to nitrite and nitrat. Additionally, the pH value of greywater is to oxidized NH4 7.71 then iron exist mainly in the form of Fe (OH)3. Thismatter has property

Fig 3.8: Concentration of NH4

- cause to changed

+ FeNH4(OH)3 +-N to NO2

- and NO3

- before and after treatment

-, NO3

(3-1) of cations when pH <7, and has property of annion when pH> 7.1 (isoelectric + is point at pH = 7.1). Therefore inside the greywater envinronment, the NH4 adsorted by Fe (OH)3 as reaction below: -+ NH4 Fe(OH)3

- of

The process of transformation from NH4 these concentration inside the grey waste water and dilute greywater (Table 3.2). Table 3.2: Concentration of NO2 Symbols Concentration of NO2 Concentration of NO2

-, NO3

-, NO3 dilute greywater (NTPL) NO2-

NO3-

NO2-

NO3-

(mg/L) Cout

(mg/L)

Cout

(mg/L)

greywater (NTNB) Cout (mg/L) 1,18±0,26

MSL3

2,17 ±0,68

1,14±0,44

1,49±0,12

MSL4

2,42±0,84

1,84±0,42

0,51±0,21

0,64±0,09

MSL5

1,87±0,6

2,41±0,34

0,14±0,11

1,16±0,12

MSL6

0,78±0,29

2,69±0,33

0,06±0,07

1,54±0,13

MSL7

0,75±0,22

2,49±0,33

0,06±0,07

1,62±0,23

--N, NO2

The result show that nitrit formed inside 1st -3rd of laterite layers; the maximum concentration of nitrit is maximum at 4th laterite layer and starting of reducing from 5th to 7th of laterite layer. After 6th -7th of laterite layer, the concentration of nitrit extremely reduced, even below the measurement limits of equipment. The concentration peak of nitrat after 6th laterite layer with greywater and after 7th laterite layer with dilute greywater.For pH > 5 always- it’s value of --N can be adsorted by laterite because these greywater, the ion of NO3 anion linked to ion Fe3+ (goethite) and Al3+ (gibsite).

The removing processes of amonium, nitrit, nitrat aremain cause to reduce the

T-N of greywater by biodegradation of microorganisms and adsortion of

laterite. The removing performance of nitrogen proportional to the number of

laterite inside the system, reaching 46.67% - 70.31% and 44.85% - 57.29%

respectively for the greywater and dilute greywater.

3—P)

3.2.2.3 Phosphorus (T-P) and phosphate (PO4

The removing processes of phosphate is main cause to reduce the T-P of

greywater by adsortion of laterite and using as nutrient of microorganism. The

removing performance of phosphate reached 87,31%-98,84% - greywater and

89,01%-97,61% - dilute of greywaterrespectively for the number of laterite

from 3 to 7 inside system. The phosphate of effluent droped very low, even

below the detection limit of the equipment - it demonstrated the phosphate

removal potential of laterite is very high (Fig 3.18Fig , Fig 3.19). The

phosphate was adsorted by geothite as reaction as below:

2- + H = Fe-OPO3

2- +H2O

2- holded on surface of laterite, it’s cause to reduce the

(3-2) Fe-OH+ HPO4

The Fe-OPO3 concentration of phosphate.

Apart from phosphorus being adsorbed by laterite, other part of phosphorus

being adsorbed by microorganisms. Phosphorus is nutrient for development of

microorganisms, it’s necessy for aerobic microorganisms as reaction as below:

+ + 1,2O2 + 0,2PO4

3- → 0,16C5H7O2 +

(3-3) C2H4O2 + 0,16NH4

1,2CO2 + 0,2(HPO3) + 0,44OH- +1,44H2O

Estimate the loading of phospho being adsorted by microorganism as below:

While: A: concentration of COD (mg/L)

x: the quality of COD be digested by

microorganism (mg/L)

NTNB

)

f o

Nước thải vào Nước thải sau MSL4 Nước thải sau MSL6

Nước thải sau MSL3 Nước thải sau MSL5 Nước thải sau MSL7

L / g m

( P - - 3

4 O P

n o i t a r t n e c n o C

4,0 3,5 3,0 2,5 2,0 1,5 1,0 0,5 0,0

3--P before and after treatment of greywater

Fig 3.18: Concentration of PO4

2,0

)

f o

1,5

NTPL

L / g m

Nước thải vào Nước thải sau MSL4 Nước thải sau MSL6

Nước thải sau MSL3 Nước thải sau MSL5 Nước thải sau MSL7

1,0

( P - - 3

4 O P

0,5

n o i t a r t n e c n o C

0,0

3--P before and after treatment of greywater

Fig 3.19: Concentration of PO4

The removing performance of T-P increased proportional to the number of 3-P. The performance of laterite layers and the reducing of T-P is lower than PO4 T-P reached range 48,13%-97,19% and 61,04%-95,04% respectively for

greywater and dilute of greywater; these performance reached more than 90% after 6th laterite layer, this performance is high.

3.2.3 Dertermination of decay rate coefficient of organics (BOD5, COD)

+-N)

and removal rate coefficient of nitrogen (NH4

+-N)

3.2.3.1 Dertermination of decay rate coefficient of organics (BOD5, COD) and removal rate coefficient of nitrogen (NH4

The decay ratio of organics (ks) determinated by equation of T. Pfeiffer, R. Malone: (3-4)

Post award above equation by logarithm and non-linear regression all

experience results of laboratory model. The result expressed at Fig 3.23, Fig

3.24, Table 3.17.

5

80 BOD5

60 )

i

40 y = Co.e-0.34x R² = 0.969

L / g m

NTNB NTPL Expon. (NTNB) Expon. (NTPL)

(

y = Co.e-0.21x R² = 0.876

g n n i a m e R

20 D O B n o i t a r t n e c n o c

0

1

2

3

4

5

6

7

8 Laterite layers

Fig 3.18: Relation between concentration of BOD5 and laterite layers

f o

150 )

i

L / g m

100

COD y = Co.e-0.22x R² = 0.835

(

NTNB NTPL Expon. (NTNB) Expon. (NTPL)

y = Co.e-0.18x R² = 0.915

g n n i a m e R

50 D O C

n o i t a r t n e c n o c

0

1

2

3

4

5

6

7

8 Laterite layers

Fig3.19: Relation between concentration of COD and laterite layers

Table 3.17: Organics decay coefficient of greywater and dilute greywater R2

No Parameters

1 BOD5

2 COD

Influent concentration ( mg/L) 76,71 34,72 136,43 66,61

Coefficient ks (layer-1) 0,34 0,21 0,22 0,18

0,969 0,876 0,835 0,915

3.2.3.2 Determination of removal rate coefficient of nitrogen.

The amonium is removed through biodegradation and adsortion processes

inside the multi soil layering system. The biodegradation ratio expressed with

Monod equation; the adsortion ratio expressed with Langmuir equation. The

process of biodegradation and adsorption occurs parallel to each other and

defined by the equation below: (3-5) r = rsinh học + rhấp phụ= k1.(C0 C) + k2.(C0 C)

Logarit of both sides are result as below: (3-6) Kt =

For dertermination of K then post award of the function (depend

on t – the number of layer); and the slope of graphs is value of K. The result expressed at Fig 3.25, Table 3.18.

NTNB NTPL

y = 0,4014x R² = 0,9698

C / o C n

l

y = 0,3828x R² = 0,8859

Laterite layers

and laterite layers Fig 3.25: Relationship between

Table 3.18: Determination of removal rate coefficient of amonia (NH4

No Parameters

Coefficient K (layer-1)

+-N) R2

1

+-N

NH4

Influent concentration (mg/L) 7,82 3,04

0,401 0,382

0,969 0,885

3.2.3.3 The mechanic of removing the main pollutants out of greywater by using laterite with multi soil layering engineering.

The chemical and physical processes and complex biological place in aerobic

zone (not flooded) and the anaerobic (waterlogged). The contaminants are

removed through filtering mechanism, adsorption, decomposition of organic

matter and nitrogen in wastewater to form complexes gray are retained in a

grade laterite or food for microorganisms; most of the processes of pollutants in

gray wastewater occurs in the upper layer of soil in aerobic conditions.

3.3 Pilot results of greywater treatment from B5-Yen Thuong bulding on-site.

The pilot model caculated base on the characteristic of greywater of influent

and effluent, flow, coefficient ks, K. Caculation and choosing of pilot model which having 6 laterite layers (MSL6-PL) with dimension LxBxH =

0,95x0,5x0,68 m. This pilot treat greywater from some apartments in B5-Yen

Thuong.

Start up process of pilot: From 1 to 13 first day of period is time to create

microorganisms; about 14-19 next days is the time for microorganisms

development; stabilization process after the 19th day onwards. Timing for start

up pilot requires at least about 13 days and showed in Fig 3.27.

8

6

NH4+-N NO2- NO3-

4 ) l / g m

(

2 n o i t a r t n e c n o C

0

11 13 15 17 19 21 23 25

Time (day)

- during start up

+-N, NO2

-, NO3

Fig 3.27: The concentration variation of NH4 process of pilot

The result of greywater treatment showed at Table 3.5 as below:

Table 3.3: Concentration and performance of greywater from B5-YenThuong building No Parameters Unit

Greywater

QCVN14:2008 /BTNMT (B)

Performance (%)

Influent 7.37±0.84

Effluent 6.95±0.65

-

pH COD BOD5 TSS

3--P

PO4

T-P

+-N

mg/L 139.40±32.66 39.63±15.63 mg/L 92.90±28.88 13.66±10.57 mg/L 164.83±52.87 15.94±56.34 0.14±0.069 mg/L 1.06±0.46 mg/L 0.62±0.48 mg/L

2.11±0.82 3.92±1.53 7.05±3.03

- 71.3±10.13 88.4±9.06 89.9±5.51 91.8±4.07 72±7.92 90.33±7.10

1 2 3 4 5 6 7

5-9 - 50 100 10 - 10

NH4

T-N

mg/L 13.34±5.32

4.37±1.97

67.76±5.63

8 -

3.3.1.1 Variation of pH

Same the results of research on laboratory model, the trending of greywater’s

pH is decrease; the largest decrease happended at the date 04/21/2014 (from

8.80 to 7.90) and smallest decrease happened at the date of 19.07.2014 (from

5.50 to 5.42). The results of pilot studying is similar laboratory models. The

variation of pH is large with higher pH of input.

3.3.1.2 Organics (BOD5, COD)

500

100

The removal performance of BOD5 reached 61.9% -90.6% (mean 88.4%) and tended to increase over time. During the the time of practice: the concentration of BOD5 ranged 25-45mg/L, the performance of BOD5 increased from 47,9% to 61% in the first month – but still this performance is lower than the results of other month; from next month the BOD5 concentrations droped below 15 mg/L. The average removal performance of the COD of model pilot reached 71.4 ± 10.13%, it’s higher than the results obtained for the MSL6 (laboratory model) was 64.5 ± 4.6% (Fig 3.28, Fig 3.29).

f o

)

400

300

L / g m

( 5

Nước thải trước xử lý Nước thải sau xử lý Hiệu suất xử lý (%)

200

100

D O B

n o i t a r t n e c n o C

500

100

Fig 3.28: Concentration of BOD5 before and after treatment of greywater

f o

)

400

300

L / g m

(

Nước thải trước xử lý Nước thải sau xử lý Hiệu suất xử lý (%)

200

100

D O C

n o i t a r t n e c n o C

Fig 3.29: Concentration of COD before and after treatment of greywater

The average COD concentration of effluent reached 39.63 ±15.6mg /L, lower

than the value specified in Regulation QCVN 14: 2008 / BTNMT but not meet

up the value which used for theoretical caculation is 30 mg/L. The main reason

is because the formula for determining the laterite layer under determined constant of COD is R2 = 0.835; furthermore, calculated results of laterite layer according COD is 6.03 but the author choiced is 6 (less than the theoretical

result). Therefore need to choose the number of laterite layer is more than

theoretical caculation.

+-N)

+-N ranged between 77,6% - 97,5%. With The treatment performance of NH4 concentration of influent ranged from 3,62mg/L to 11,9mg/L then concentration

+-N concentration of influent effect on NH4

3.3.1.3 Nitrogen (T-N) and amonia (NH4

of effluent reached below 1 mg/l. Not see any relationship which expressed that +-N concentration of the NH4 effluent. This thing also recognized through research of laboratory models (Fig

3.30).

)

100

%

)

f o

L / g m

(

Nước thải trước xử lý (mg/L) Nước thải sau xử lý (mg/L) Hiệu suất xử lý (%)

N - +

4 ( e c n a m r o f r e P

H N

n o i t a r t n e c n o C

+-N before and after of greywater treatment

Fig 3.30: Concentration of NH4

The treatment performance of T-N is lower than the treatment performance of +-N, ranged between 56% -76.9%. This peformance is higher than NH4 peformances of avaiable technology in Vietnam nowaday, such as active slugde, A2O, SBR, anerobic tanks …which collection results from every wastewater treatment plants. And SBR or A2O technology usually applied to big capacity while multi soil layering engineering towards to small and medium capacity.

3--P)

3--P from B5 Yen Thuong building ranged between 0.3- The concentration PO4 3--P 3.45 mg/L (mean 2.60±0.54 mg/L). The treatment performance of PO4 reached the maximum value is 97% ((1/4/2014) and the minimum value is 86% (21/5/2014) but has signal of light reducing since July 2014. Treatment performance of phosphate decreased to: phosphate is treated by adsorption and chemical biology, over time developing microbial membrane reduces the absorption capacity of laterite but increased biological absorption capacity.

3.3.1.4 Phosphorus (T-P) and Phosphate (PO4

However the speeds of chemical adsorption is faster than biological adsorption, it’s cause make treatment performance of phosphate has been come down light.

100

(Fig 3.32).

)

f o

L / g m

Nước thải trước xử lý (mg/L) Nước thải sau xử lý (mg/L) Hiệu suất xử lý (%)

( P - - 3

4 O P

n o i t a r t n e c n o C

3--P before and after treatment of greywater Fig 3.32: Concentration of PO4

Treatment performance of T-P ranged 63.9% -86.1% (mean 72.4%). concentration of T-P input is about 0.85- 6.30 mg/L (mean 3.92 mg/L) after passing through 6 laterite layers then fell down to 0,32- 1.86 mg / L (mean 1.0 mg/L).

3.3.1.5 Suspended solids total

The suspended solid total (TSS) was removed very effective through filtering

mechanism and the absorption capacity of microbial membranes which

surrounding the laterite. The average removal efficiency of TSS reached 89.6%;

and increase over time effectively hold TSS increase over time through

sediment accumulation and development of microbial membranes. This is also

the reason that can clog system in the future. Therefore need to retain the ability

to keep the TSS at acceptable levels for extended working period for the

system.

3.3.2 Proposed technological solutions for greywater treatment by using laterite with Multi Soil Layering engineering.

The Multi Soil Layering engineering with main laterite material can apply to treat greywater from buildings in Hanoi city. The Multi Soil Layering systems was built underground then area of land occupied is small, not effect much the environmental landscape, simple operation. The quality of effluent from MSL6- PL reached Regulation QCVN 08-MT:2015/BTNMT (B1) – National

Technical Regulation on surface water (unless microorganism parameter) and Regulation QCVN 14:2008/BTNMT(B) – National Technical Regulation on domestic wastewater.

CONCLUTION AND RECOMMENDATION

1. Conclution

a. The organics (BOD5 and COD) of effluent significantly decreased after each laterite layers. The treatment performance reached 77.22- 90.60% of BOD5 and 70.50-80.33% of COD – with greywaterand reached 45,72 – 71,61% of BOD5 and 26,31-59,32% of COD - with dilute greywater, when laterite layers were increased from 3 to 7; The removing of BOD5 occurred mostly inside the first 3 laterite layers while the removing of COD were only effective from 6th laterite layer. the organic treatment performance. The organic treatment performance is proportional to the organic pollutant concentration of influent;

1-4th inside laterite respiration cellular and

b. Ammonium is removed via two stages of nitrification: (1) the growth of heterotrophic microorganisms that take oxygen from the environment airs and happen of layers autotrophicmicroorganismsthat take oxygen from –O-H-O-H-O group and +is adsorbed by the hydroxyl happen inside the lower laterite layer; (2) the NH4 group(inside the mineral structure of laterite). The treatment performance of +) reached 66,49% - 94,58% - with greywater and 79,68% - amonium (NH4 89,91% - with dilute greywater, corresponding withthe laterite layers from 3 to 7.

c. Phosphate is removed by the ion absorbencyof the iron hydro oxite that exist on the surface of laterite and the Phosphate comsumption e of microorganisms. The performance of phosphate is high inthe first 3 laterite layers and reached over 98% after the 5th laterite layer,without the dependance on the phosphate concentration of influent. This proves that the potiential of phosphate removing is very high.

d. The biodegradation rate coefficient (ks) of BOD5 are 0.34 (layer-1) and 0.21 (layer-1); of COD are 0.22 (layer-1) and 0.18 (layer-1) and the removing rate coefficient (K) are 0.401 (layer-1) and 0.377 (layer-1) –in greywater and dilute greywater, respectively.

treatment meets

e. For model of pilot, the average treatment performance of BOD5 is +-N is 90,31±7,10 (%); T-N is 88,61±9,00(%); COD is 69,72±6,21 (%); NH4 +-P is 91,81±4,01 (%); T-P is 72±7,92 (%) – These 67,81±5,60 (%); PO4 performances are in the range of results which obtained from research on laboratory models. The greywater after the National Regulations such as QCVN 14:2008/BTNMT (B) và QCVN 08:2008/BTNMT (B1).

2. Recomendations

a. During 3 months for of research, the microbial membrane observed had signs beenincreasing at top of laterite layer but the blockage was had not happened. To maintain long working time and avoid the blockage for multi soil layering system, necessary solutions on limiting excessive growth of microbial membranes need to be studied;

b. This researchis proceeded withclosed pipeline and inside the laboratory without the external factors,such as rain water, temperaturewhich can affect on the treatment performance of contaminants inside the grey wastwater. Thereforewhen building the multi soil layering outdoor, more researchs on effect of these factors on the treatment performance of multi soil layering system should be implememted;

c. The effection of the hydrolic loading, dimesion of laterite unit, structure of laterite inside the multi soil layering system, ratio between laterite units and heat laterite to performance of greywater treatment didn’t study. Must do more than researchs about these designal parameters;

d. The research object is greywater without any heavy metals, it’s interaction (if any) with wastewater source having similar parameters can effect the mentioned treatment performance;

e. Researching and adding safety coefficientto reduce the difference between theory and practice in the equationof determining the number of laterite layer.

LIST OF PUBLISHED SCIENCE

1. Khuong Thi Hai Yen, Pham Thị Minh Thu, Nguyen Thi Kim Cuc,

Nguyen Thi Hang Nga. “Studying the capacibility of greywater

organics by using laterite with MSL engineering”, Supply and

Sewage Journal, page 75-77, volume 1+2, 2015.

2. Khuong Thi Hai Yen, Pham Thị Minh Thu, Nguyen Thi Kim Cuc,

Nguyen Thi Hang Nga. “Studying the capacibility of greywater

amonia by using Multi Soil Layering system”, Proceeding of the

annual conference on water resources, page 301-303, November

2014.

3. Khuong Thi Hai Yen, Pham Thị Minh Thu, Nguyen Thi Kim Cuc,

“Studying the greywater characteristics from building in Ha noi