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 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 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: tanh@vkttv.edu.vn 218 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] 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 [4], Ly Tien river in China territory has 11 reservoirs with nine of them in operation, Ban Long river in China territory has hydropower reservoirs under planning with many of them in operation, Nguyen river has operating plant Some hydropower plants on Ly Tien river, upstream of Da river taken from satellite is shown in Figure Figure 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 and 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 /s ) 1200 1000 800 600 400 200 15/VI 15/VII 14/VIII Time 13/IX 13/X Figure 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 /s ) 1400 1200 1000 800 600 400 200 15/VI 15/VII 14/VIII Time 13/IX 13/X Figure 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 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 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 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 August 2605 16 June 2145 15 August 1730 July 1860 August 2217 August 2870 10 August 2030 20 July 1380 September 2030 20 July 6920 11 October 3880 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 August 1855 17 June 1860 22 August 1400 August 1660 June 2944 14 July 3370 15 August 1370 28 July 1560 August 1070 25 August 4250 11 October 2920 August 1590 10 August 1150 18 August 1060 11 October Table 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 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 222 T.H Thai, L.T Anh / VNU Journal of Science, Earth Sciences 26 (2010) 218-223 Table 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 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 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 (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 Center for Advanced Material Technology – National Center for Technological Progress, C6 Thanh Xuân Bắc, Hanoi, Vietnam VNU University of Science, 334 Nguyễn Trãi, Hanoi, Vietnam Received 17 April 2015 Revised 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 hours but increased MLSS to 12000 mg/L Keywords: Membrane bioreactor (MBR), piggery wastewater, microfiltration, activated sludge, eutrophication 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: amt.met@gmail.com 47 48 N Sáng et al / VNU Journal of Science: Earth and Environmental Sciences, Vol 31, No (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 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 – 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 Schematic of the submerged membrane bioreactor system N Sáng et al / VNU Journal of Science: Earth and Environmental Sciences, Vol 31, No (2015) 47-53 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 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 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 Figure Effect of HRT on removal COD 50 N Sáng et al / VNU Journal of Science: Earth and Environmental Sciences, Vol 31, No (2015) 47-53 The results on Figure shown that the concentration of organic matter in the influent was very high, average COD parameter was 4160 mg O2/L After 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, 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 The concentration of ammonium in the influent was very high, 320 mg/L in average After 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 Effect of HRT on removal ammonium T-P removal efficiency with time is shown in Figure N Sáng et al / VNU Journal of Science: Earth and Environmental Sciences, Vol 31, No (2015) 47-53 51 Figure Effect of MLSS on removal COD Figure 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 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 shown that when increased MLSS in tank to 12000 mg/L, COD removal efficiency increased to 70% after 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 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 52 N Sáng et al / VNU Journal of Science: Earth and Environmental Sciences, Vol 31, No (2015) 47-53 Figure 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 shown that efficiencies of ammonium removal of systems with 12000 mg/L and 6000 mg/L after 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 Figure 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 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 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 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 (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, Bioresourece Technology 87 (2003), pp 103 – 111 [2] Tazi-Pain, A., Schrotter, J.C., Bord, G., Payreaudeau, M and Buisson, H Recent, Improvement of the BIOSEP process for industrial and municipal wastewater treatment, Desalination, 2002, 146, pp 439 – 443 [3] Urbain, V., Trouve, E and Manem, J, Membrane bioreactors for municipal wastewater treatment and recycling, In Preprints Water Quality Int’l 96-18th IAWQ Biennial Int’l Conference & Exhibition, Singapore, 1996, pp 317 – 323 [4] Davies, W.J., Le, M.S and Heath, C.R, Intensified activated sludge process with submerged membrane microfiltration, Wat Sci Tech, 1998, 38(4 – 5), pp 421 – 428 53 [5] Tran Huu Uyen, Study on design and manufacture small-scale system wastewater treatment by MBR technology, A final report of Project Ministry of Industry and Trade, 2013 (In Vietnamese) [6] Truong Thanh Canh, Study on piggery wastewater treatment by upflow sludge blanket filteration, Science & Technology Development, Vol 13, No M1 – 2010, pp 48 – 58 (In Vietnamese) [7] Le Van Cat, Treatment of high nutrient content wastewater, Sciences and Technology Publishing House, Hanoi, 2007 (In Vietnamese) [8] Lee, D.S., C.O Jeon and J.M Park, Biological nitrogen removal with enhanced phosphate uptake in a sequencing batch reactor using single sludge system, Water Res, 2001, 35: 3968 – 3976 [9] Lin Y.M., Tay J.H., Liu Y., and Hung Y.T, Biological nitrification and denitrification processes, Biological Treatment Processes, Handbook of Environmental Engineering, Volume 8, 2009, pp 539-588 Khảo sát ảnh hưởng số yếu tố ảnh hưởng đến hiệu xử lý nước thải chăn nuôi lợn sử dụng bể sinh học kết hợp lọc màng (MBR) Nguyễn Sáng1, Chu Xuân Quang1, Trần Văn Quy2, Trần Hùng Thuận1 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 xử lý nước thải chăn nuôi lợn thực tế bể sinh học hiếu khí tích hợp màng lọc quy mơ phịng thí nghiệm thực Mục tiêu nghiên cứu nhằm đánh giá ảnh hưởng thời gian lưu thủy lực nồng độ bùn hoạt tính Nước thải chăn ni lợn có nhu cầu ơxy hóa học, hàm lượng amoni phốt cao (tương ứng 4200 mgO2/L, 320 mg/L 48 mg/L) sử dụng nghiên cứu Kết cho thấy hiệu suất loại bỏ COD đạt khoảng 94% điều kiện làm việc thời gian lưu 24 nồng độ bùn 6000 mg/L, nhiên cần tăng thời gian lưu gấp đôi để đạt hiệu suất loại bỏ NH4+-N T-P tương ứng 99% 85% Hiệu suất tương đương đạt rút ngắn thời gian lưu xuống tăng nồng độ bùn lên 12000 mg/L Từ khóa: Xử lý sinh học kết hợp lọc màng (MBR), nước thải chăn ni lợn, vi lọc, bùn hoạt tính, phú dưỡng  ... 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... 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... 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