VIETNAM ACADEMY OF SCIENCE AND TECHNOLOGY MINISTRY OF EDUCATION AND TRAINING
GRADUATE UNIVERSITY OF SCIENCE AND TECHNOLOGY -----------------------------
TRINH XUAN DUC
RESEARCH AND APPLICATION OF AMMONIA
REMOVAL IN GROUNDWATER ON THE TREATMENT
SYSTEM USING MOVING BED BIOFILM CARRIERS
MAJOR: ENVIRONMENTAL ENGINEERING CODE: 9 52 03 20
SUMMARY OF THESIS IN ENVIRONMENTAL ENGINEERING
HA NOI – 2018
The work was completed at: Graduate University of Science and
Technology - Vietnam Academy of Science and Technology.
Facilitator 1: Assoc. Prof. Tran Duc Ha
Facilitator 2: Assoc. Prof . Ngo Quoc Buu
Reviewer 1:
Reviewer 2:
Reviewer 3:
The thesis will be defended before the Examining Board at the
Academy level, meeting at the Graduate University of Science and
Technology - Vietnam Academy of Science and Technology at ...
............................ 2018.
The thesis can be found at:
- Library of the Academy of Science and Technology
- National Library of Vietnam
1
INTRODUCTION
1. THE RESEARCH NECESSITY OF THE THESIS
The demand for clean and hygienic water is always a top
concern and has become a strategy of many countries including
Vietnam. Currently, the living standard in our country is being
improved gradually, awareness of health protection is increasing,
especially in big cities like Hanoi. This is the second most populated
area in the country with a population of about 7 million people in
2014. However, along with the development of many aspects of the
capital, the issue of clean water access has not been met in both
quantity and quality.
The survey results of the Northern Hydrogeological -
Engineering Geological Division showed that the ammonia
concentration in groundwater in Hanoi has exceeded many times
compared to the permitted standards, in which some places are 10-20
times higher.
The biggest concern about ammonia is that the intermediates
such as nitrite and nitrate compounds are formed from ammonia in
the treatment process and use of water for domestic and drinking
purposes under the following mechanism: During the water
treatment process, there always formed naturally Nitrosomonas
bacteria in the filtration tank, which converts part of the ammonia in
groundwater into nitrite intermediates. With sufficient conditions,
under action of a different type of bacteria that is naturally formed in
the filtration tank as Nitrobacter, the nitrite intermediates will be
further transformed into nitrate. While there is insufficient evidence
to assess the extent and direction of the effects of ammonia-based
2
-, NO3
- is - are the agents that cause red blood cell
products on the human body, the harm caused by NO2
-, NO3
well known. NO2
damage in children and may be cancer-causing agents.
One of the few technologies that can meet these
requirements is Moving Bed Biofilm Reactor (MBBR) which uses
biofilm on the carriers moving in water when it is operating. Its
treatment efficiency is only lower than the fluidized bed reactor and
much higher than other techniques. Its operation is much simpler
than the fluidized bed reactor that requires a high automative level.
Most of the materials and equipment of the MBBR
technology are easy to find and manufactured domestically.
Based on the above facts, the topic "Research and
application of ammonia removal in groundwater on the treatment
system using moving bed biofilm carrier" was selected for this
thesis. 2. OBJECTIVES AND CONTENTS OF THE THESIS
2.1. Objectives of Research
- Research on ammonia removal in groundwater in Hanoi
with the concentration of less than 25mg/L (20mgN/L) by
simultaneous Nitrification and Denitrification process in the
equipment using MBBR with porous carriers (DHY) of a high surface area of about 6,000-8,000 m2/m3, high porosity and light
weight, easily moving in water without addition of substrates.
- Research and design of the treatment equipment using
integrated DHY carriers including MBBR tank and self-cleaning
filter tank for ammonia removal in groundwater in order to ensure
clean water standard for eating and drinking purposes, suitable with
3
the investment ability and operational conditions in Vietnam.
2.2. Contents of Research
(1) Collect data and survey the current status of exploitation
and technological line of water plants in Hanoi area in order to
evaluate groundwater quality, ammonia pollution and influential
factors such as pH, temperature, alkalinity, organic matters,
phosphorus and ammonia treatment efficiency of existing production
lines.
(2) An overview of ammonia treatment methods in the
country and the world, analyze advantages and disadvantages and
raise the existing problems.
(3) An overview of ammonia treatment by microbiological
method to understand the treatment mechanism, various types of
microorganisms, influential factors and kinematic reaction models as
the basis for selecting the pilot models, analyzing and evaluating the
results obtained on the experimental model and field pilot model.
(4) An overview of biofilm and the works using this
technology, evaluating the advantages and disadvantages of each
type of biofilm, each type of work for which to propose moving bed
biofilm carriers to use for design of ammonia removal system in
ground water in Hanoi.
(5) Experimental research on laboratory model: Batch and
SK/g N-NH4
continuous experiments are made to determine kinematic parameters such endogenous degradation factor kp (d-1), biomass efficiency Y (g +), ammonia semi-saturation indicator Ks (mgN/L), substrate consumption coefficient k (μ/Y). Assessing the factors that
affect the nitrification process: ammonia input, dissolved oxygen
4
concentration (DO), carrier density, number of reactor
compartments. Assessing the factors that affect the simultaneous
denitrification process in aerobic medium, effect of substrate
concentration and establishing experimental equation for specific
denitrification rate (U).
(6) Designing and constructing an integrated module for the
MBBR system using porous DHY carriers at the field, pilot run to
test kinematic parameters and building a data set for design
calculations.
2.3. Scope
Groundwater in Hanoi area where the ammonia concentration
(NH4+) is less than 25 mg/L (20 mgN/L), including urban and rural
areas. It can also be applied to water plants in other areas where water
is contaminated with ammonia including surface water.
2.4. Subject
- DHY carrier has a large surface area of 6000-8000 m2/m3 with simultaneous nitrification and denitrification process under
aerobic condition.
- The system uses MBBR integrated with self-cleaning filter
(DHK).
2.5. Experimental research
- Conducting two types of experimental model: batch and
continuous experiment for ammonia nitrogen treatment with water
samples simulated from actual groundwater quality, in which the + < limitations of research and fluacutation are as follows: NH4 50mgN/L, temperature ranges from 25-30oC, organic matters are
negligible, phosphorus concentration ranges from 0,5-1,5 mg/L, pH:
5
7,2-8,0, alkalinity ranges from 200-300 mg(CaCO3)/L.
- Batch experiment: Assessing the effects of retention time,
density of the carriers, oxygen concentration, substrate and the
number of reaction compartments, from which the optimal
parameters could be given for nitrification and dennitrification
process.
- Continuous experiment: The model is designed based on
the parameters obtained from batch experiment to determine the
kinematic parameters for nitrification and denitrification for DHY
carrier.
- Designing an integrated MBBR and DHK tank with capacity of 5m3/h for ammonia removal in order to verify the
kinematic parameters obtained in the laboratory in Yen Xa water
plant, Thanh Tri district.
6
CHAPTER 1.
OVERVIEW OF AMMONIA REMOVAL IN
GROUNDWATER BY APPLICATION OF MBBR
TECHNOLOGY
1.1. Overview of ammonia pollution situation in Hanoi
Most of groundwater in Hanoi has an iron concentration of
3-20 mg/L which is much higher than the clean water standard of 0.3
mg/L. In addition, the concentration of manganese and organic
matters in some areas is about 1 - 5 times higher than the clean water
standard of maganese as 0.3 mg/L and organic matter as 2mg/L.
Particularly, the south and southwest of Hanoi is polluted with
ammonia (NH4 +) with a very high ammonia concentration of 5-25
mg/l (3.8-20 mgN/L) compared to the clean water standard of 3
mg/L (2.3 mgN/L).
Currently, the water treatment technology in Hanoi is mainly
to remove iron, manganese in the groundwater using the processes of
aeration, sedimentation, contact and rapid filtration. The effluent
quality complies with the national standard QCVN 01: 2009/BYT
except the ammonia that is almost untreated. According to the
survey results, the ammonia concentration is about 10-20% lower
than the input level. As a result, the ammonimum concentration
remains 5-20 mg/L (4-18 mgN/L) in the water supplied for the city,
which is higher than the standard of 3 mg/L (2.3 mgN/L).
1.2. Ammonia removal by biological method
The bio-based ammonia treatment can be carried out in three
main processes: (1) conventionally nitrification and denitrification;
(2) Anammox is an anaerobic ammonia oxidation process in which
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ammonia and nitrite are directly reduced into nitrogen gas; (3)
Sharon is the partial nitrification process, its product is also nitrite
and then denitrified into nitrogen gas as the principle of "hopping"
treatment of the process. The Anammox and Sharon processes can
save about 25% of the oxygen and 40% of the organic matters, but
require rigorous and relatively complicated control during operation.
Therefore, this thesis focuses on the conventional ammonia
treatment method, that is nitrification and denitrification into
nitrogen gas.
1.3. Biofilm technique
1.3.1. Biofilm carrier
The DHY carriers are made of polyurethane by the Vietnam
Construction and Environment Joint Stock Company (VINSE). Its
surface area is calculated based on the geometrical dimension of the
substrate and its porous structure. The very small holes inside the
substrate creates surfaces for the growth and development of
microorganisms; The diffusion and metabolism mechanism is
similar to the fixed biofilm. Thus, the biomass transfer process in
the moving carrier system is higher than that of the fixed carrier
system.
The DHY carrier is made of polyurethane (PU) with high
porosity of 92-96%, large surface area which can be up to 15,000 m2/m3 (normally from 6,000 to 8,000 m2/m3). Due to the porous
structure of the carrier, it has a very low specific gravity of about 33 kg/m3, the substrate is highly flexible, limits the movement of oxygen out of the tank by which the pressure and volume of gas
8
required for the tank is reduced, save energy and reduce operating
costs. The carriers in the tank accounts for about 20-30%.
1.3.2. Moving Bed BioFilm Reactor (MBBR)
The biofilm technology is a common solution in many water
treatment plants, such as BF, Rotating Biological Contactors (RBC),
submerged biofilm with various types of filtration materials. The
carriers in the tank accounts for a very high percentage (usually from
40-100%), but their ammonia treatment efficiency is not high (only
about 60-70%), the structure is large and easily clogged. The
Moving Bed Biofilm Reactor (MBBR) solves the remaining
problems in the reactors using fixed biofilms such as reducing the
volume of structure, reducing energy costs, and significantly
increasing the efficiency of ammonia treatment to about 90-95%.
1.4. Research situation in Vietnam and the world
Currently, the ammonia treatment technology requires to
build many tanks to separate the treatment processes, the carriers
used have small surface area, high density, and requires to
supplement the substrate for denitrification or water circulation,
strict control of oxygen concentration, much energy consumption
and complicated operational management.
The biofiltration method using MBBR allows an increase in
microbial density per unit volume to ten times higher than the
activated sludge technique and thus, it significantly increases the
treatment efficiency. On the other hand, there is an occurence of
self-selection and enhancement of the density of slow-growing
microorganisms in the biofilm. The operation of the treatment
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system faces the difficulty in the biomass transfer (providing food
for microorganisms in biofilm of thickness up to mm) for high-
density microorganisms. The Fluidized Bed and Moving Bed
Biofilm Reactor (MBBR) are developed to promote the biomass
transfer in the treatment system, overcome the constraints of other
biofilm techniques such as Trickling Filter, Biological Rotating
Reactor, subermerged filter.
The MBBR is less efficient than the Fluidized Bed because
of its lower carrier area but it has the advantage of simple operation,
suitable for medium and small-sized treatment scale in Vietnam. The
operation of the Fluidized Bed system requires a very high
automation.
Therefore, the next step is to integrate the biological
processes on appropriate bio-carriers and integrate the tanks in
modular form.
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CHAPTER 2. SUBJECT AND RESEARCH METHODOLOGY
2.1. Scope and subject of the research
The scope of the reasearch is Hanoi groundwater.
The research subject is ammonia treatment system using
DHY carriers, integrated with self-cleaning filter. This equipment is
installed behind the existing rapid filter of Yen Xa water plant
(filtered water and undisinfected with activated chlorine). The
capacity of the field pilot is 5m3/h. The nitrification and
denitrification processes inside the carrier in aerobic conditions, the
determination of kinematic parameters, the calculated parameters
through the batch and continuous experimental system in laboratory.
Implementing design and field pilot run in order to inspect the
results and propose a set of parameters for calculation and design of
the ammonia treatment system for ground water.
Pilot run is to verify the results and propose calculation
parameters, design MBBR module.
2.2. Determination of kinematic parameters
2.2.1. Nitrification
In order to design a water treatment system based on a
kinematic model, the kinematic constants must be known.
Characteristic values for kinematic process including the
substrate consumption coefficient k (μ/Y), the semi-saturation
indicator Ks, endogenous degradation constant kp, can only be
determined from experiments with respect to a specific experimental
system.
The experimental system is a reactor containing the
concentration of microorganism X which agitates and operates
11
continuously (where the inflow rate is equal to the outflow rate, the
substrate concentration in the inflow is S0, the outflow is S. The
concentration of microorganisms in the inflow is X0 (g/l), the
outflow is Xe (g/l).
The substrates are used by microorganisms to synthesize
cells, a part enters in biochemical reaction in order to generate
energy, the number of microbiological cells formed correspond to
the loss of substrate in the system. Then, the cell growth rate
Vg(g/l.d) is defined by the formula:
(2-16) (2-16)
Where μ (1/d) is the specific correlation coefficient for each
microbial species or specific growth constant. vsu is the substrate
decrease rate, accordingly:
(2-17) (2-17) vg = -Y.vsu
Where Y is the biomass efficiency, which means that when
an amount of substrate is consumed, a certain amount of biomass
(g/g) is produced, the sign (-) indicates two opposite processes.
However, the need for materials to grow microorganisms in
accordance with the expression (2-17) is rarely satisfied. When it
does not meet the major demand, the growth rate will decrease,
which is attributable to the change in specific growth constant value,
so according to Monod kinematics, μ is calculated as follows:
(2-18) (2-18)
Combining equations (2-16), (2-17) and (2-18), we have:
12
(2-19) (2-19)
Or the rate of substrate decline is also defined:
(2-20)
Using a continuous agitation experimental system, then, the
cell retention time is defined:
(2-21) (2-21)
In which:
Qw: Flow rate of water-sludge mixture entering the sludge
tank
Qe: Flow rate getting out of the reactor
V: Reactor volume
X, Xe, Xr: Density of microorganism in the reactor in the
inffluent and effluent.
Accordingly, the equilibrium equation describing the
variation in biomass density and the substrate concentration is
expressed as follows:
(2-22)
In which:
g: Real biomass growth rate
Q: Influent rate equal to Qe
g = vg + vp = -Yvsu – kp.X (2-23)
X0: Microbiological concentration in the influent v, v, (2-23)
V: Volume of reaction block
13
In a stable operating state with microbial density X, the
microbial density does not change over time dX/dt = 0. The
concentration X0 in the influent is usually very small so X0=0.
From the equation (2-22) and (2-23):
(2-24)
Divide 2 sides by X:
(2-25)
The left side of the equation is the inverse of the sludge age,
then (2-24) is rewritten:
(2-26)
Combining the equation (2-18) and (2-19) we have:
(2-27)
Where the specific substrate consumption coefficient k means the ability to consume substrate per unit of formed biomass.
(2-28)
Combining 2-27 and 2-28 we have:
(2-29)
Divide two sides by X,
(2-30)
Linearization of (2-30) by inversion:
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(2-31)
If we consider the left-hand side (2-31) as a function, 1/S is a
variable, we obtain the linear equation with the slope (Ks/S and the
vertical cutoff is 1/k), accordingly k, Ks could be calculated.
The values kp and Y are defined as follows: Using the
relation of the expression (2-26) and taking 1/ as a function, vsu/X
is a variable, from which Y and kp could be determined.
2.2.2. Denitrification
As the denitrification is heterotrophic aeration process, so
experiment made to calculate the kinematic parameters is using for
the organic matter consumption process, as it is the control element
of denitrification process. The kinematic model established to
describe denitrification include Monod and empirical models.
The denitrification rate can be expressed as:
U = k (2-32)
U = k.X (2-33)
Where k is the constant of reaction rate, X is the
concentration of microorganisms.
With the continuous-flow reaction technique, the
denitrification efficiency and reaction rate are calculated from
experiments by the formula:
(2-34)
(2-35)
(2-36)
15
Accordingly, the rate of specific substrate consumption for
nitrate is calculated by the formula:
(2-37)
r/X means the rate of substrate consumption per unit of mass
(concentration) of microorganisms, which is called the specific
denitrification rate U.
Then, the equation (2-37) is written as follows:
(2-38)
In which, the cell retention time is calculated according to
the formula (2-21), since Xe equals 0 then the equation (2-21) is
written as follows:
(2-39)
The hydraulic rention time shall be written as below:
(2-40)
Combining the equation (2-38) and (2-40), the specific
denitrification rate is rewritten by the formula:
(2-41)
The relationship between microbiological activity and the
rate of substrate degradation could be bee seen that microorganisms
with a fast growth rate will give a good ability of pollution
treatment. Based on this relationship, it is possible to use the cell
retention time ( ) to control the treatment process without
16
determining the effective biomass concentration or amount of
substrate used by the microorganism.
degree, representing the equation U = f(c) into U = k.c
If the equation is U = f(c), then the equation is calculated in -n, drawing the equation with experimental data with y = U, x = c, then the
coefficient of reaction rate k and the reaction degree n are
determined.
2.3. DHY carrier
The DHY carrier manufactured by Vietnam Construction
and Environment Joint Stock Company (VINSE) was selected for
testing. DHY has dimensions of 1cm x 1cm x 1cm and testing is
conducted in order to determine technical parameters of DHY when
the carrier has no microorganisms, including: real density, apparent
mass, porosity, porous volume, surface area.
2.4. Laboratory model
2.4.1 Batch experiment diagram
The experiment is installed using batch reactor process with
a 36-liter rectangular box reactor. The carrier in the reactor has been
cultured with a stable density. The
air supply system is placed side
by side with the tank. Air is
supplied by an air compressor to
maintain the movement of the
carrier and supply oxygen to the
nitrification process. The purpose
Figure 2.1. Batch experiment diagram
of the batch experiment is to
the effect of the
determine
17
ammonia concentration on the reaction rate, to investigate the
density of the carrier to the nitrification rate, to investigate the effect
of the oxygen concentration, the effect of substrate.
Experimental diagrame is shown in Figure 2.1, depending on
the experimental purpose, the density of the carriers varies from 5% + concentration varies from 10 mgN/L to 50 -30% and the N-NH4
mgN/L.
2.4.2. Continuous experiment diagram
The integration of many reactors will reach the features of
an ideal upward flow, which means that the reactor in this case
operates in a stable state because the tank is quite long and is not
agitated, therefore the concentration of a particular component in the
flow varies with the position
along the flow. The
longitudinal concentration
fluctuations are caused by
Figure 2.2. Experimental
the longitudinal diffusion
diagram of reactor
process and chemical
reaction, its concentration is
high at the inlet and low at
the outlet along the length of
Figure 2.3. Experimental
the reactor
diagram of 2 successive reactors
The continuous flow
expirement aims at
determining the kinematic
parameters of water
Figure 2.4. Experimental
systems. The
diagram of 3 successive reactors
treatment
18
continuous flow experiments are carried out with different models: 1
reactor, 2 reactors and 3 successive reactors. Kinematic parameters
are calculated through experiments. The 5-liter cylinder reactors are
supplemented with the carriers, which are equivalent to 20% of the
tank volume and are connected successively. The experimental
diagrams in the figures from 2.2 to 2.4 will be tested with an input
ammonia concentration ranging from 10-50 mgN/L and appropriate
alkalinity and phosphorus.
2.5. Pilot MBBR model
2.5.1. Pilot installation site
Based on the results of the kinematic parameters determined
from the laboratory model to calculate the MBBR pilot design, capacity of 5 m3/h.
Yen Xa clean water plant in Thanh Tri district with capacity of 6.000 m3/day can supply clean water for Yen Xa commune with 4
groundwater wells. Pilot model will be installed after the existing
iron treatment process. The filtered water is led into the ammonia
treatment system before disinfection.
2.5.2. Pilot operation and sampling
After pilot installation, the equipment for pilot run in
continuous operation of 24 hours will be tested, air is supplied to
ensure a complete agitation in the aerobic compartment. Flow rate is
adjusted to increase from 1-5m3/h in a period of 1 month, then
operate continuously in 3 months with design flow rate and take
daily post-treatment samples to check the parameters of ammonia,
nitrite, nitrate and alkalinity.
19
CHAPTER 3. RESULTS AND DISCUSSION
3.1. Biofilm Carrier
Basic Parameters
The DHY carrier is made of polyurethane with 5 samples
including M1, M2, M3, M4, M5, which have the percentage of
additives of 0%, 5%, 10%, 15%, 20% respectively. The respective
result is an apparent mass of 0.021-0.027 g/mL; real density of
0.203-0.283 g/mL, porosity of 92.7-93.8%; Surface area of 6000- 8000 m2/m3.
3.2. Determination of kinematic parameters
3.2.1. Nitrification process
Nitrification rate
The k and n values in Table 3.5a shall be replaced in the
equation 2-6: with the ammonia output of 3 mg/L
(2.3mgN/L) according to QCVN. Accordingly, the average value of
nitrification rate is determined as 16.25 mgN/L.h converted to ammonia treatment load by 20% carrier as 1950.00 gN/m3.day.
Calculating the substrate consumption coefficient k and
the semi-saturation indicator Ks from experiment
From Table 3.7, the calculated k and Ks results show that the
substrate consumption coefficient increases with decreasing N-NH4
+ concentration, with the k value of 0.4-0.6. The semi-saturation
indicator Ks also fluctuates around the mean value as 1. The Ks
between 0.92-1.13 is consistent with the research.
Determining biomass efficiency Y and endogenous
degradation coefficient kp
It can bee seen from the diagram that the biomass efficiency
20
Y and endogenous degradation coefficient kp could be calculated.
There are several comments on biomass formation as follows: When
the ammonia concentration increases, the biomass efficiency tends to
reduce from 0.1 to 0.38. The low kp value demonstrates a high
capability of maintaining of microorganisms’ activity in the
treatment system, which ranges from 0.01-0.04.
3.2.2 Determining the specific denifitration rate equation (U)
in the aerobic tank system.
Based on the Table 3.11, the mean values k and n can be
selected according to the data regression chart for the experimental -n. The k equation for the calculation of denitrification rate U = k.c
value ranges from 0.04 to 0.48 and n ranges from 0.6 to 1.08.
3.3. Actual pilot MBBR model
- Designing Pilot MBBR in Yen Xa to verify the selected
kinematic parameters shows a similarity between the laboratory and
actual pilot models. The kinematic parameters are selected as
follows:
- The kinematic parameters in nitrification process
Table 3.24. The kinematic parameters in nitrification process
Value Parameters Range Represenatative
+-N)
Y efficiency 0.1 – 0.38 0.25
0.41 – 0.61 0.55
0.92 – 1.13 1.00
degradation 0.01 – 0.04 0.035
Biomass (gSK/gNH4 Substrate consumption coefficient k (d-1) Semi-saturation indicator Ks, NH4+ (gN/m3) Endogenous coefficient kp (d-1)
21
- Experimental equation of denitrification rate in aerobic
conditions and use of substrate from endogenous degradation
Table 3.25. Kinematic factor of specific denitrification process
Value Parameter
K factor N factor Range 0,04 - 0,48 0,6-1,08 Representative 0,4 0,6
-0,6
The formula for calculating the denitrification rate: U=0,4.c
CONCLUSION AND RECOMMENDATION
CONCLUSION
1. A research on MBBR technology with biofilm carrier
applied for ammonia removal in groundwater in Hanoi shows that
the nitrification and denitrification processes in the same aerobic
condition still reach a high efficiency as well as the practical
application to deal with ammonia pollution in drinking and domestic
water of the people in Hanoi ensuring the permissible standards
(QCVN01: 2009/BYT).
2. The thesis also demonstrates that the denitrification
process has been carried out in the biofilm with the substrate as the
endogenous degradation process which assures a 30% nitrate
removal efficiency without the addition of substrates.
3. The pilot results of ammonia treatment system with the designed capacity of 5m3/h with the integration of MBBR and DHK
tank using 0.7-1.2 mm quartz sand, the input ammonia concentration
of 20 mgN/L, 2 hour-hydraulic retention time under aerobic
22
conditions without substrate addition still ensure ammonia treatment
to reach the permissible standard.
4. This thesis has provided a set of parameters for
calculation and design of ammonia treatment system in groundwater
in Hanoi, which is the MBBR technology with DHY substrate of 6,000- 8,000 m2/m3 surface area, specific weight of about 20-50 kg/m3, the carrier density is 20% of the tank volume. With the integration of MBBR and DHK, the ammonia treatment structure
becomes one block instead of four blocks of conventional
technology (nitrification tank, denitrification tank, strengthened
aeration tank and filter). RECOMMENDATIONS
1. The research limit of this thesis is removal of ammonia of
less 25mg/L (20 mgN/L) concentration in groundwater without
substrate addtion for denitrification process. Therefore, it is
necessary to study to add the substrate and circulate water to speed
up the denitrification process in order to treat polluted water with
higher ammonia concentration.
2. Continuing the research on ammonia remmoval in
groundwater by the application of new processes such as Anammox
or Sharon to increase the treatment efficiency and save energy.
3. Continuing the research for development of porous
carriers to increase the mechanical durability and hydrating ability.
4. It is recommended to use the research results of thesis as
foundation for the research and application of ammonia removal in
groundwater in Hanoi to meeting QCVN01: 2009/BYT standards on
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ammonia, nitrite and nitrate in order to ensure the access to clean
water for the people in Hanoi and extends to other localities in
Vietnam. CONTRIBUTION OF THE THESIS
- The DHY carrier has large surface area which allows the
integration of nitrification and denitrification processes in the same
treatment tank right in the aerobic compartment .
- The denitrification process does not require the addition of
substrate but use the substrate from the endogenous degradation.
- MBBR tank and self-cleaning filter are integrated in a
module to remove ammonia in groundwater in Hanoi.
24
THE PUBLISHED RESEARCHES OF THE AUTHOR
RELATED TO THE THESIS
1. Trinh Xuan Duc, Le Anh Tuan, Doan Manh Hung, Tran Viet Dung. Wastewater treatment technology by Moving Bed Biofilm Reactor (MBBR).Vietnam Water Supply and Sewerage Magazine, No. 6 (87). October/2012.
2. Trinh Xuan Duc, Tran Viet Dung. Domestic wastewater treatment by intermittent biological treatment technolog. Magazine of Water Supply and Drainage, 5 (86). T82012.
3. Trinh Xuan Duc, Le Anh Tuan, Doan Manh Hung, Dao Nhu Y, Nguyen Thi Thanh Hoa, Phan Thi Phuong Thao, Nguyen Van Hoang. Simultaneous treatment of organic matters (BOD5) and +-N) in domestic wastewater for Da Lat city ammonia nitrate (NH4 using MBBR technology. Vietnam Water Supply and Sewerage Magazine, Number 1 + 2 (99 + 100), T1 + 3/2015.
4. D.X. Trinh, A.T. Le, H.M Doan Manh, H.T.T. Nguyen, + removal H. D. Pham & B.V. La (Vietnam), 2014. Study on N-NH4 from Undergroundwater by MBBR case study in Bach Khoa Ward - Hanoi, Vietnam. Sustainable water and sanitation services for all in a fast changing world, Construction Publishing House. HaNoi, 2014,pp:855 – 860.
in Ha Noi. The 12th treatment
5. Trinh Xuan Duc, Tran Duc Ha, Le Anh Tuan, Nguyen Thi Thanh Hoa and Nguyen Thi Viet Ha (VietNam), 2016.Application of the simultaneous process of Nitrification and for Denitrification by using Moving Bed Biofilm Reactor groundwater International Symposium on Southeast Asian Water Environment (SEAWE2016). Hanoi, Vietnam, November 28-30, 2016.
