Development of cooperative research on assessment of climate change impacts on water resources of Vietnam-China transboundary river basins

VNU Journal of Science, Earth Sciences 26 (2010) 218-223

Development of cooperative research on assessment of climate
change impacts on water resources of Vietnam-China
transboundary river basins
Tran Hong Thai, Luong Tuan Anh*
Vietnam Institute of Meteorology, Hydrology and Environment,
23/62 Nguyen Chi Thanh, Hanoi, Vietnam
Received 2 November 2010; received in revised form 16 November 2010

Abstract. Vietnam-Chinese transboundary river basins play an important role in socio-economic
development for both Vietnam and China. The cooperative research on assessment of climate
change impact on water resources is necessary in order to maintain and develop water resources,
exploit and consume effectively, protect environment and prevent disasters on transboundary river
basins. The problems have been paid the attention by scientists and agencies of both countries.
This report presents the expressions of climate change impacts on water resources on VietnamChina transboundary river basins and suggest cooperative content and methodology of the
research.
Keywords: climate change, Vietnam-China transboundary river basins.

1. Introduction∗

economic development of Vietnam and China.
The main upstream rivers of Hong River
system, include: Ly Tien (upstream of Da
River), Nguyen River (upstream of Thao river )
and Ban Long river (upstream of Lo river)
located in the South of China has more
abundant water resources and hydropower
potential than the similar ones in the North. Ky
Cung- Bang Giang river system, having amount
of 9-10 km3 per year, flowing into China

territory, is also vital for socio-economic
development on downstream area of Ta Giang
river basin. Thus, protection and maintenance
of water resources aimed to exploit and utilise
resources effectively, preserve environment and
prevent disasters is crucial and paid the

Along Vietnam-China border, the river
flowing into Vietnam is Hong River, with
81.200 km2 upstream area located in China and
1.100 km2 area in Laos, the river flowing out is
Ky Cung –Bang Giang River, with 10.532 km2
upstream area located in Vietnam, flowing into
Ta Giang River in Guangxi, China. According
to the recent research [1], total discharge
volume of Red River, resulting from foreign
territory is 48,7 km3 per year, equivalent to
38.2% of total water amount of Hong River.
The both river systems are important for socio-

_______
∗

Corresponding author. Tel.: 84-4-38343506
E-mail:

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T.H. Thai, L.T. Anh / VNU Journal of Science, Earth Sciences 26 (2010) 218-223

attention by scientists and agencies of both
countries [2, 3].

2. The expressions of climate change impacts
on water resources of Hong River basin
Climate change due to the earth warming
causes the change of the processes, such as
ocean-atmosphere interaction, ocean circulation
over continents, hydrological cycle, also may
lead to changes in distribution of water
resources in space and time. Results of national
and international research show that climate
change impacts may increase the uncertainty of
hydro-meteorological parameters, leading to
more frequent occurrence of extreme
hydrological characteristics. Natural disasters
related to flood and drought occurring

219

frequently over the world and the region in
recent year is the sign of the above statements.
Meanwhile,
due to socio-economic
development and population growth, demand of
water resources on upstream area of Hong
River system is highly growing, especially
many reservoirs have been build for the
purposes of hydropower, irrigation and others.

Based on data of Power Engineering Consulting
Joint Stock Company 1 [4], Ly Tien river in
China territory has 11 reservoirs with nine of
them in operation, Ban Long river in China
territory has 8 hydropower reservoirs under
planning with many of them in operation,
Nguyen river has 1 operating plant. Some
hydropower plants on Ly Tien river, upstream
of Da river taken from satellite is shown in
Figure 1.

Figure 1. Hydropower plants on Ly Tien river.


220

T.H. Thai, L.T. Anh / VNU Journal of Science, Earth Sciences 26 (2010) 218-223

Unstable water inflowing from China
territory due to operation of hydropower plants
at upstream results in large daily water level
fluctuation which is contrast to natural law:
daily water fluctuation is around 1.5-2.0m on
Da river at Muong Te, 0.5-1.0m at Nam Giang,
1.0-1.3m on Lo river at Ha Giang and 0.5-0.8m
on Gam river at Bao Lac. Regulation activities
of reservoirs in China make the tendency of
drought flow a month faster. Discharge in the
first months of November-December of dry

season decreases quicker than the previous
periods. Flow regulation of reservoirs at Ly
Tien Do station, upstream of Da river (basin
area of 17.155 km2) far about 52 km from
Vietnam-China Border is shown in Figures 2
and 3. The instability of flow from China
disturbs the operation of structures in
exploitation and utilisation of water as well as
usual status of ecosystem, downstream of Hong
river system.

1600
1400

Naturally restored
regulated

D is c h a rg e (m 3 /s )

1200
1000
800
600
400
200
0
15/VI

15/VII

14/VIII
Time

13/IX

13/X

Figure 2. Naturally restored daily flow and regulated flow at Ly Tien Do station in 2010.
1800
Naturally restored

1600

regulated
D is c h arg e (m 3 /s )

1400
1200
1000
800
600
400
200
0
15/VI

15/VII

14/VIII
Time

13/IX

13/X

Figure 3. Naturally restored daily flow and regulated flow at Ly Tien Do station in 2009.


T.H. Thai, L.T. Anh / VNU Journal of Science, Earth Sciences 26 (2010) 218-223

One significant expressions of climate
change impacts on water resource in upstream
of Hong river is occurrence of the annual
maximum flood in October which is the last
month of flood season when the storage
capacity of reservoirs are nearly full. Statistical
data in Table 1 shows that the annual maximum
flood on Ly Tien river and Nguyen river often

221

occurs in August (taking more than 50%). In
recent years, two the annual maximum flood
occurred in October 2006 and October 2010.
Consequently, artificial floods appeared on 11th
October 2006 with flood peak nearly twice than
natural one (Table 2), this made flood
magnitude suddenly 10m higher on 8th-12th
October 2006 at Muong Te station.

Table 1. The appearance of annual flood peak at October, period of recharge of reservoirs
in recent years in upstream of Da and Thao rivers in China territory.
No.

Year

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16

1973
1974
1975
1976
1977
1978
2001

2002
2003
2004
2005
2006
2007
2008
2009
2010

Ly Tien Do station on Ly Tien river
Peak flow rate (m3/s) Date/ Month
2434
27 July
3720
5 August
2605
16 June
2145
15 August
1730
5 July
1860
7 August
2217
1 August
2870
10 August
2030
20 July

1380
8 September
2030
20 July
6920
11 October
3880
4 August
1770
19 July
2300
19 August
1770
10 October

Man Hao station on Nguyen river
Peak flow rate (m3/s) Date/Month
2265
28 July
3415
6 August
1855
17 June
1860
22 August
1400
1 August
1660
1 June
2944

14 July
3370
15 August
1370
28 July
1560
9 August
1070
25 August
4250
11 October
2920
4 August
1590
10 August
1150
18 August
1060
11 October

Table 2. Artificial flood occurred in October 2006 at Ly Tien Do station on Ly Tien river
(upstream of Da river).
Flood
1-4 August 2007
8-11 October 2006

Rainfall (mm)
Trung Ai Kieu Tho Kha Ha
163
152

162

Another expression related to climate
change impacts on water resource is that
although in recent years, water resource in
Hong river system tended to decrease but
extreme flood occurring in Hong River system
had tendency of increasing in frequency.
Statistics in Table 3 shows that extreme floods

158

Muong Te
120,6
131,8

Flood peak (m3/s)
Ly Tien Do Muong Te
3880
5359
6920

6505

used to occurred once every 8-10 years in the
last period. From 2001 up to now, extreme
floods occurred on Da river in 2002 and 2006,
on Thao river in 2005 and 2008 and on Lo river
in 2001 and 2008. It is noteworthy for flood
prevention for Hong river delta.

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T.H. Thai, L.T. Anh / VNU Journal of Science, Earth Sciences 26 (2010) 218-223

Table 3. The increasing frequency of great flood occurrence on river branches of Hong river system
Da river (Hoa Binh station)
Annual flood peak exceeds 15000m3/s

1964
1969
1971

17200
15800
16200

1996

22640

Thao river (Yen Bai station)
Annual flood peak
Year
exceeds 7000 m3/s
Period of 1960-1990
1968
10100
1971

9860
1979
7450
1986
7510
Period of 1991-2000
1996
7010

2002
2006

15100
15200

Period of 2001-2010
2005
7450
2008
10800

Year

Floods on 6-7 January 2003 with the peak
flood of 1320 m3/s at Lao Cai station on Thao
river (annual peak flood of 1860 m3/s on 16
August) is the unprecedented abnormalities that
may related to climate change impacts.
The increasing uncertainty of hydrological
characteristics due to climate change impacts

reduces reliability of hydrological engineering
calculation as well as accuracy of forecast and
warning, leading to reduce operation efficiency
of water regulation structures and raise natural
and manmade disaster risk.
The risks related to climate change impacts
on water resources on Vietnam-Chinese
transboundary river basins can be reduced
based on promoting information exchange,
scientific
research
and
management
cooperation. Currently, the trend of cooperation
on climate change study, integrated water
resources management in the region and the
world create the opportunities to develop
cooperation on the basis of equitable and
reasonable utilization of water resources, and
obligation not to cause significant harm on river
basins, crossing the border of two countries.

Lo river (Genh Ga station)
Annual flood peak
Year
exceeds 7000 m3/s
1969
1971
1986

8100
11700
8720

1995
1996

7380
7930

2001
2008

8200
7050

3. Cooperative research on climate change
impacts to enhance sustainable development
of water resources on Vietnam-Chinese
transboundary river basins
According to the research of international
experts [5], cooperation should be started with
information exchange, cooperative research and
development of general principles of integrated
management of international river basins.
Cooperative research and rational use of
transboundary water would turn risks and
challenges into cooperative opportunities.
The objectives
- Exchange results of hydrological and

water resources research on rivers acrossing the
border, including: Da river, Thao river, Lo
river, Ky Cung river and Bang Giang river;
- Assess rainfall and surface water of
transboundary river basins in space and time;
- Assess the water demand in space and
time;
- Tendency of rainfall and surface water in
recent years;
- Develop climate change scenarios of the
region;


T.H. Thai, L.T. Anh / VNU Journal of Science, Earth Sciences 26 (2010) 218-223

223

- Assess impacts of climate change
scenarios on rainfall-runoff process, water
balance on the river basins which take an
account of socio-economic development on
transboundary river basins;

propose solutions of integrated water resources
management in order to develop and sign
agreements to deal with problems related to
transboundary water between Vietnam and
China.

- Propose to respond climate change and

mitigate adverse impacts of water exploitation
on rivers crossing Vietnam-China border.

References

Cooperative research
Information and data exchange on the basis
of authorisation; Methodology unification;
Cooperative research; Workshop on research
exchange; Training. Research funding need to
be co-financed by two governments.

4. Conclusion and suggestion
In the context of climate change, based on
the friendship and good neighborliness of two
countries, recognition of riparian interest as
well as understanding of risks related to
transboundary water, cooperative research on
hydrology and water resources is necessary to

[1] Tran

Thanh

Xuan,

Hydrological

characteristics of water resource on
rivers in Vietnam, Agricultural Public House,

Hanoi, 2007 (In Vietnamese).
[2] F. Yan, H. Daming, Transboundary water
vulnerability and its drivers in China, J. Geogr.
Sci. No. 19. (2009).
[3] Luong Tuan Anh, Tran Thuc, Transboundary
water issues affected to Vietnam in the context
of climate change, Proceedings of the fifth
Conference of Asia Pacific Association of
Hydrology and Water Resources, Hanoi, 2010.
[4] Power Consultancy Company I, Report on
Investment of Lai Chau hydropower plant on Da
river, 2009.
[5] P. Van der Zaag, F. Jaspers, J. Gupta,
Legislation of international waters, UNESCOIHE Institute for Water Education, Delft, 2007.


VNU Journal of Science: Earth and Environmental Sciences, Vol. 31, No. 2 (2015) 47-53

Determination of Operation Factors in Treating Piggery
Wastewater by Membrane Bioreactor
Nguyễn Sáng1,*, Chu Xuân Quang1, Trần Văn Quy2, Trần Hùng Thuận1
1

Center for Advanced Material Technology – National Center for Technological Progress,
C6 Thanh Xuân Bắc, Hanoi, Vietnam
2
VNU University of Science, 334 Nguyễn Trãi, Hanoi, Vietnam
Received 17 April 2015
Revised 4 May 2015; Accepted 22 July 2015

Abstract: An investigation into the treatment efficiency of real piggery wastewater of a benchscale aerobic membrane bioreactor was performed. The experiments were aimed to evaluate the
effects of hydraulic retention time and activated sludge concentration. The piggery wastewater
having high chemical oxygen demand, ammonium and total phosphorus concentrations (about
4200 mg/l, 320 mg/L and 48 mg/L, respectively) was employed. It was found that the removal
efficiency of COD reached up to 94% even at operation conditions of HRT = 24 hours and MLSS
= 6000 mg/L, but the HRT need to be increased twice in order to obtain the removal of 99% NH4+N and 85% T-P. The similar efficiency was also achieved by reduced HRT to 8 hours but
increased MLSS to 12000 mg/L.
Keywords: Membrane bioreactor (MBR), piggery wastewater, microfiltration, activated sludge,
eutrophication.

1. Introduction∗

contribute to eutrophication [1]. However, it is
difficult to treat nitrogen by the conventional
activated sludge process. The organic matter
oxidation microorganism has a high yield value
than the nitrification microorganism. Therefore,
if sludge retention time (SRT) gets shorter, it is
hard to stabilization the nitrification
microorganism. In this study, the membrane
bioreactor (MBR) was used to make high mixed
liquor suspended solids (MLSS) and long SRT
for advanced nitrification. Comparison with
conventional activate sludge processes, the
MBR process offers several advantages. The
membrane is an absolute barrier to suspended
solids and thus offers the possibility to operate

Due to containing high amount of organic
matter, nitrogen, phosphorus and suspended

solids, piggery wastewater created an important
environmental impact. The free ammonia is
toxic to fish and many other aquatic organisms;
moreover, both ammonium ion and ammonia
are oxygen-consuming compounds which
deplete the dissolved oxygen in receiving water.
In addition, all forms of nitrogen can be made
available to aquatic plants and can consequently

_______
∗

Corresponding author. Tel.: 84-435544821.
Email:

47


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N. Sáng et al. / VNU Journal of Science: Earth and Environmental Sciences, Vol. 31, No. 2 (2015) 47-53

the system at high sludge concentration. The
treatment process run at longer SRT so that the
slow-growing microorganisms can be enriched.
This leads to better removal of organic matter
as well as efficiency of nitrification [2], higher
effluent quality, complete disinfection, high
reliability compactness and minimized sludge
production [3]. Therfore, treatment of high

contaminated wastewater by using MBR with
consistance conditions might have promising
many potential [4].
In Vietnam, the MBR technology used test
few years ago and main applied in the treatment
of domestic sewage, industrial wastewater and
hospital wastewater [5]. Research publications
in the MBR applying for piggery wastewater
treatment are limited. Therefore, the study of
factors affecting the operation factors of MBR
systems in piggery wastewater treatment is
necessary to make a precondition for the
application of this technology for piggery
wastewater treatment in Vietnam.

2. Materials and methods
2.1. Materials

grew with real piggery wastewater in one
month as starting-up phase.
- Membrane used in this study was
polyvinylidene fluoride (PVDF) hollow fiber
(Motimo, China). It has pore size of 0.1 µm and
membrane surface area is 0.065 m2 per module.
2.2. Methods
+ Analysis method: analysis method of
COD parameter follow by TCVN 6491:1999
(ISO 6060: 1989) NH4+-N: follow by TCVN
6620 – 2000 (ISO 6778:1984); MLSS follow by
TCVN 6625:2000 (ISO 11923:1997), and T-P

follow by TCVN 6202:2008 (ISO 6878:2004).
+ Experiment design: A hollow fiber
membrane module was submerged in a process
tank with a working volume of 50 L. An airdiffuser was set up at the beneath the membrane
module in order to provide oxygen for
biological oxidation and reduce membrane
fouling. The rate of aeration was controlled by
using a valve and measured by flow-meter.
Membrane transport pressure was taken by
pressure meter. The range of DO value is 3 – 6
mg/L. MBR process was operated at constant
permeate flux 12 L/m2.h.

- Piggery wastewater was collected from a
pig farming households (Thuong Tin, Hanoi).
The wastewater was taken at the discharged
drainage of breading facilities. The wastewater
which removed coarse garbage (>5 mm in size)
was having COD arround of 4200 mg/l,
ammonium of 320 mg/L and total phosphorus
concentrations of 48 mg/L.
- Concentrated activated sludge was taken
from the aerobic tank of an existing biological
treatment system which was operating with
synthesis wastewater. Activated sluge was then

Figure 1. Schematic of the submerged membrane
bioreactor system.

N. Sáng et al. / VNU Journal of Science: Earth and Environmental Sciences, Vol. 31, No. 2 (2015) 47-53

3. Results and discussion
3.1. Characterization of activated sludge
MLSS, MLVSS and SVI parameters were
measured in order to observe the growth rate of
sludge.
(I)

Figure 2. The change of MLSS, MLVSS and SVI
with the time.

From results in Figure 2, after 18 days, the
amount of biomass increased from 1217 mg/L
to 6513 mg/L. From the beginning to sixth day,
microorganisms in sludge were in the period of
adaptation to the environment cause low growth
of activated sludge. At growth stage of
microorganism with piggery wastewater is rich
in substances and nutrients, sludge grew upto
6000 mg/L and was settling well. Settling
ability of sludge (solid – liquid separation
ability in reactor) is performed by SVI
indicator. The sludge with low SVI is good
settling and concentrated. SVI of sludge in the
tank was fluctuated in range of 68 – 132 mL/g.
Thus, the feed sludge has good settling ability.
However, there were some period that settling
ability of sludge was not good (for example
from 22nd to 26th SVI > 100 mL/g), because the

large of air flow provided; sludge floc break out
and became finer. Low DO made sludge float
on the top and took long time to settle down. At
the next stage, sludge developed well, but slows

49

settling, had sticky smell. When microelement
substances added, SVI fluctuated in range of 80
– 98 mL/g, in optimal range 80 – 120 mL/g [6].
Comparison with Truong Thanh Canh study [6]
which activated sludge feed by piggery
wastewater had SVI of 77 mL/g, was lower
than sludge in this study.
In order to access microorganism
concentration in activated sludge, the ratio
MLVSS/MLSS was examined. The results on
Figure 2 shown that when solid retention time
increase, the concentration of both MLSS and
MLVSS in tank increase, so bacteria was good
growth. Besides, the ratio MLVSS/MLSS was
quite stable, fluctuate in 0.71 – 0.84. It could
conclude that sludge had high degree of
activity.
3.2. The effect of hydraulic retention time on
treatment efficiency
3.2.1. The effect of hydraulic retention time
on removing organic matter
Study was carried out at 6000 mg-MLSS/L,
aerated rate 15 L/min with different hydraulic

retention time (HRT): 2, 4, 6, 8, 24 and 48
hours.
The efficiency of COD removal is shown in
Figure 3.

Figure 3. Effect of HRT on removal COD.


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N. Sáng et al. / VNU Journal of Science: Earth and Environmental Sciences, Vol. 31, No. 2 (2015) 47-53

The results on Figure 3 shown that the
concentration of organic matter in the influent
was very high, average COD parameter was
4160 mg O2/L. After 2 hours of aeration,
efficiency of COD removal process achieved
37.1% corresponding to 2620 mg/L of COD in
the effluent. When the aeration time increased
to 4, 6, 8 hours, the efficiency of COD removal
increased by 53% to 75.2%. After 24 hours of
aeration, the efficiency of COD removal
achieves 93.6%. When the time of aeration
increased to 48 hours, COD removal efficiency
increased slightly to 94.3%. The results shown
that after 24 hours in aeration, the
biodegradable organic matter was almost
completely treated, only remained hard or nonbiodegradable
organic
substances

in
wastewater.
3.2.2. The effect of hydraulic retention time
on removal ammonium
The efficiency of ammonium treatment is
shown in Figure 4.
The concentration of ammonium in the
influent was very high, 320 mg/L in average.
After 8 hours of aeration, almost of ammonium
had not changed into nitrate or nitrite form, as a
result was only 39 % (shown in Figure 4).
Because both of oxidation process of ammonium
and COD occur in the aerobic condition by two

types of autotrophic and heterotrophic
microorganisms, there was a competition for
factors joining in two processes, example such
as dissolved oxygen. The autotrophic organism
(Nitrosomonas and Nitrobacter) could not
compete with heterotrophic microorganisms
because its concentration normally too small in
total biomass. Moreover, ammonium oxidation
rate by autotroph (the amount of ammonium is
oxidized in unit of time and biomass) is too
smaller than that one by heterotrophic
organisms (only equal 40 – 50%) [7]. That
means scale of equipment for oxidation of
ammonium process is double than oxidation of
ammonium with the same loading rate [7]. As a
result, in order to Nitrosomonas and

Nitrobacter bacteria convert totally NH4+ to
NO2- and NO3-, longer time is needed. The time
of aeration increase to 24 and 48 hours,
ammonium treatment efficiency increased to
75.5 % and 99.0 %, respectively, indicating that
nitrification occurred almost completely. So, in
compared with COD removal process need only
24 hours for oxidation of simple organic matter,
then ammonium oxidation needs a longer time
by 48 hours. Therefore, the objective that needs
to study in the aerobic treatment process is
ammonium oxidation process, COD oxidation
is a minor factor. Having solved ammonium
oxidation process then COD oxidation process
will be solved automatically [7].
From results above, HRT of 48 hours was
selected for the next step in the study.
3.2.3. Effect hydraulic retention time on
removal phosphorus
Piggery wastewater contains large amount
of phosphorus (45 – 140 mg/L) which is the
main cause of eutrophication.

Figure 4. Effect of HRT on removal ammonium.

T-P removal efficiency with time is shown
in Figure 5.


N. Sáng et al. / VNU Journal of Science: Earth and Environmental Sciences, Vol. 31, No. 2 (2015) 47-53

51

Figure 6. Effect of MLSS on removal COD.
Figure 5. Effect of HRT on T-P removal efficiency.

T-P removal efficiency increased with the
increased of HRT (shown in Figure 5). These
efficiencies after 24 hours and 48 hours
achieved 81.3% and 84.9%, respectively. Due
to the increased and got predominant of the
number of bacteria- P. This type of bacteria has
low degradable rate but has ability to absorb
large amount of phosphorus in sludge and
deposition so T-P removal efficiency increase
[8]. Besides, by good at sludge separation of
membrane bioreactor, the amount of
phosphorus in effluent was also reduced [7].
The average T-P concentration in the effluent
was smaller than 10 mg/L.
3.3. The effect of the activated sludge
concentration (MLSS) on treatment efficiency
3.3.1. Effect of MLSS on COD removal
Study was carried out in two activated
sludge tanks at the same time with
concentrations of 6000 and 12000 mgMLSS/L.
The effect of MLSS on efficiency of COD
removal is shown in Figure 6.

Because piggery wastewater is rich in

nutrients, so the biological system still operates
as well as when increase of MLSS (demand of
using substrate of microorganisms increase).
The aeration tank in the MBR system could
cultivate and maintain a higher biomass
concentration than one of the conventional
activated sludge process. Results on Figure 6
shown that when increased MLSS in tank to
12000 mg/L, COD removal efficiency increased
to 70% after 2 hours, which is higher
significantly than one’s of system with 6000
mg/L (only achieve 37%). Due to larger
biomass should absorption substrate taken place
faster. After 8 hours, the efficiency of COD
removal of the system with 12000 mg/L was
equivalent with one’s of the system with 6000
mg/L after 24 hours (94,1% and 93,6%,
respectively).
3.3.2. Effect of MLSS on
removal

ammonium

The effect of MLSS concentration on
efficiency of ammonium removal is shown in
Figure 7.


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N. Sáng et al. / VNU Journal of Science: Earth and Environmental Sciences, Vol. 31, No. 2 (2015) 47-53

Figure 7. Effect of MLSS on removal ammonium.

When high MLSS make an increase in
number of Nitrosomonas and Nitrobacter
bacteria, so enhance nitrification in aerobic
process [9]. Indeed, the efficiency of
ammonium removal of sludge system with
12000mg/L is higher significantly than that one
of the system with 6000mg/L. Results on
Figure 7 shown that efficiencies of ammonium
removal of systems with 12000 mg/L and 6000
mg/L after 2 hours reached 54,4% and 9,8%,
respectively. These efficiencies after 24 hours
and 48 hours achieved 94.6% and 99.8%,
respectively. Base on high MLSS for advanced
nitrification,
ammonium
is
completely
converted to nitrate in the aeration tank, so
treatment process was saved time and energy.
3.3.3. Effect of MLSS on phosphorus removal
The effect of MLSS on T-P removal
efficiency is shown in Figure 8.

Figure 8. Effect of MLSS concentration on T-P
removal efficiency.

The efficiency of T-P removal of activated
sludge system with 12000 mg/L achieved
94.6%; it is higher than that one with 6000
mg/L (84.9%). High MLSS make increase in
number of bacteria-P and predominant when
increase retention time [8]. Moreover, T-P may
be removed by the filtering of membrane [7].
When MLSS increased, the efficiency of T-P
removal increased. The T-P concentration in
effluent was smaller than 6 mg/L, which meet
Vietnam’s standard for livestock wastewater
discharge (QCVN 40:2011/BTNMT).
Finally, high biomass concentration in a
bioreactor is one of the most important
conditions to remove COD, NH4+-N, T-P in
swine wastewater treatment.
4. Conclusions
The effect of HRT and the activated sludge
concentration on contaminant treatment was
defined through operate system of aerobic tanks
integrate membrane bioreactor at different
retention time and different from sludge
concentration. The results shown that with HRT
24 hours, activated sludge system 6000 mg/L
treated nearly completely simple organic
substances, biodegradable, achieved 94% in
efficiency. When extended HRT, the efficiency
of COD removal increased slightly, the
efficiency of ammonium removal increased to
99%, and for TP achieved 84.9%. When

increased the activated sludge concentration to
12000 mg/L, the time for organic matter
decompose reduced to 8 hours, efficiency
achieved 94.2% and efficiency of ammonium
and T-P removal achieved 99.8% and 94.6%
after 48 hours. The MBR is an efficient
treatment technology for COD and nutrient
removal, capable of achieving effluent with
very low NH4+-N, T-P concentrations from
piggery wastewater.


N. Sáng et al. / VNU Journal of Science: Earth and Environmental Sciences, Vol. 31, No. 2 (2015) 47-53

References
[1] D. Obaja, S. Macé, J. Costa, C. Sans, J. MataAlvarez, Nitrification, denitrification and
biological phosphorus removal in piggery
wastewater using a sequencing batch reactor,
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Khảo sát ảnh hưởng của một số yếu tố ảnh hưởng đến
hiệu quả xử lý nước thải chăn nuôi lợn khi sử dụng
bể sinh học kết hợp lọc màng (MBR)
Nguyễn Sáng1, Chu Xuân Quang1, Trần Văn Quy2, Trần Hùng Thuận1
1

2

Trung tâm Công nghệ Vật liệu - Viện Ứng dụng Công nghệ, C6 Thanh Xuân Bắc, Hà Nội, Việt Nam
Trường Đại học Khoa học Tự nhiên - Đại học Quốc Gia Hà Nội, 334 Nguyễn Trãi, Hà Nội, Việt Nam

Tóm tắt: Nghiên cứu hiệu quả xử lý nước thải chăn nuôi lợn thực tế của bể sinh học hiếu khí tích
hợp màng lọc quy mô phòng thí nghiệm đã được thực hiện. Mục tiêu của nghiên cứu nhằm đánh giá
ảnh hưởng của thời gian lưu thủy lực và nồng độ bùn hoạt tính. Nước thải chăn nuôi lợn có nhu cầu
ôxy hóa học, hàm lượng amoni và phốt pho cao (tương ứng 4200 mgO2/L, 320 mg/L và 48 mg/L) đã
được sử dụng trong nghiên cứu. Kết quả cho thấy hiệu suất loại bỏ COD đạt được khoảng 94% ở điều
kiện làm việc thời gian lưu 24 giờ và nồng độ bùn 6000 mg/L, tuy nhiên cần tăng thời gian lưu gấp đôi
để đạt được hiệu suất loại bỏ NH4+-N và T-P tương ứng 99% và 85%. Hiệu suất tương đương cũng đạt
được khi rút ngắn thời gian lưu xuống 8 giờ nhưng tăng nồng độ bùn lên 12000 mg/L.
Từ khóa: Xử lý sinh học kết hợp lọc màng (MBR), nước thải chăn nuôi lợn, vi lọc, bùn hoạt tính,

phú dưỡng.