BUI XUAN THANH | Ho Chi Minh City University of technology (original) (raw)

Papers by BUI XUAN THANH

GeoScience Engineering, 2019

Nowadays, with the salient advantages of the seawater desalination process, membrane distillation... more Nowadays, with the salient advantages of the seawater desalination process, membrane distillation (MD) technology has received increased interests to achieve desalination application. As a heat-based technology, by using the hydrophobic membrane, MD provides high efficiency in the desalination process of seawater, RO water and other solutes with high concentrations of dissolved solids. Besides, this is an alternative technology to significantly reduce the environmental impacts of traditional desalination technologies commonly used, such as distillation or reverse osmosis. In many factors affecting the desalination capacity of the membrane distillation system, membrane module configuration has a strong influence in evaluating the economic and technical efficiency of the technology. This review aims to assess the suitability of MD technology under different perspectives on the current types of membrane module configurations that include flat sheet, tubular, hollow fibre and spiral wound membranes. In addition, the evaluation of the advantages and disadvantages of the membrane module configurations will guide further studies to improve the shortcomings of existing MD technologies.

ABSTRACT The quality of raw water of Sai Gon River has been degraded in terms of an increase of p... more ABSTRACT The quality of raw water of Sai Gon River has been degraded in terms of an increase of pollutants such as organic substances, nitrogen and pathogen due to poor water pollution control of agricultural, industrial and domestic activities in the upstream region. ...

ABSTRACT This study aimed to optimize the operational parameters of oxidation processes in removi... more ABSTRACT This study aimed to optimize the operational parameters of oxidation processes in removing the non-biodegradable matters from the permeate of membrane bioreactor (MBR) which is used to treat dyeing and textile wastewater. The MBR was operated at the ...

ABSTRACT Aerobic granule was formed and stably in the sequencing batch airlift reactor with the s... more ABSTRACT Aerobic granule was formed and stably in the sequencing batch airlift reactor with the seafood- processing wastewater at different organic loading rates (OLR) and nitrogen loading rates (NLR). At the N/COD ratio of 0.1, the COD removal efficiency was ranging from 94 to 96 % for OLR of 2.6 – 7.2 kg COD/m3.d. The TKN removal efficiency was 93, 94 and 79 %, respectively. At the varied N/COD ratios, the TKN removal efficiency was approximately 95 % for the NLR of 0.3 and 0.6 kg N/m3.d (N/COD of 0.1-0.2). The TKN removal efficiency reduced to 66% at the NLR of 0.9 kg N/m3.d. In general, nitrification process occurred completely at the OLR less than 4.8 kg COD/m3.d and the NLR less than 0.6 kg N/m3.d. The simultaneous organic and nitrogen removal was effective at the OLR of 2.6-4.8 kg COD/m3.d and the NLRs of 0.3 - 0.6 kg N/m3.d.

ABSTRACT This study evaluated the treatment efficiency of four plants, namely Axonopus compressus... more ABSTRACT This study evaluated the treatment efficiency of four plants, namely Axonopus compressus (2); Melampodium paludosum (3); Tradescantia spathacea compacta (4); Catharanthus roseus (L) G. Don (5), in the wetland roof system (WR). Five WRs (including ...

ABSTRACT Up-flow multi-layer bioreactor (UMBR) is a hybrid system using dual sludge that consists... more ABSTRACT Up-flow multi-layer bioreactor (UMBR) is a hybrid system using dual sludge that consists of an up-flow multi-layer bioreactor as anaerobic/anoxic suspended growth microorganisms followed by an aeration tank. The UMBR acts as a primary settling tank, anaerobic/anoxic reactor, thickener which requires low energy due to mixing by up-flow stream. This study focused on using a pilot UMBR plant with capacity of 20-30 m3/day for domestic wastewater in HCMC. HRTs of UMBR and aeration tank were 4.8 h and 7.2 h, respectively. The average MLSS of UMBR ranged from 10,000-13,600 mg/l SS. Internal recycle rate and sludge return were 200-300% and 150-200%, respectively. The results obtained from this study at flow rate of 20 m3/day showed that removal of COD, SS, TKN, N-NH4, T-N, and color were 91%, 87%, 86%, 80%, 91% and 91%, respectively.

Bioresource Technology, 2014

IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 2014

ABSTRACT Mangrove forests provide important ecosystem goods and services for human society. Exten... more ABSTRACT Mangrove forests provide important ecosystem goods and services for human society. Extensive coastal development in many developing countries has converted mangrove forests to other land uses without regard to their ecosystem service values; thus, the ecosystem state of mangrove forests is critical for officials to evaluate sustainable coastal management strategies. The objective of this study is to investigate the multidecadal change in mangrove forests in Ca Mau peninsula, South Vietnam, based on Landsat data from 1979 to 2013. The data were processed through four main steps: 1) data preprocessing; 2) image processing using the object-based image analysis (OBIA); 3) accuracy assessment; and 4) multitemporal change detection and spatial analysis of mangrove forests. The classification maps compared with the ground reference data showed the satisfactory agreement with the overall accuracy higher than 82%. From 1979 to 2013, the area of mangrove forests in the study region had decreased by 74%, mainly due to the boom of local aquaculture industry in the study region. Given that mangrove reforestation and afforestation only contributed about 13.2% during the last three decades, advanced mangrove management strategies are in an acute need for promoting environmental sustainability in the future.

Desalination, 2010

This study investigates the sludge and effluent characteristics of a new process of coupling an a... more This study investigates the sludge and effluent characteristics of a new process of coupling an aerobic granular sludge bioreactor with a membrane filtration. The effluent and mixed liquor of sequencing batch airlift reactor (SBAR) were analyzed at various aeration shear stresses when fed with high nitrate containing wastewater. The presence of nitrate nitrogen and aerobic/anoxic condition was able to improve the sludge characteristics in terms of biomass retention, density and settling ability in SBAR. MLSS and SVI could reach 9 g/L and 44 mL/g respectively at the aeration rate of 0.6 cm/s. The presence of nitrate and the denitrification process could minimize the fouling potential. The membrane fouling can be better correlated to SBAR sludge characteristics than biomass concentration. The high aeration rate in the reactor increased the fouling resistance due to production of large MW soluble microbial products (30-50 kDa). The soluble fraction of SBAR effluent contained mainly hydrophilic substances when nitrate is present in the wastewater.

Environmental Engineering Science, 2013

ABSTRACT This is the first study on application of a sponge-membrane bioreactor (sponge MBR) for ... more ABSTRACT This is the first study on application of a sponge-membrane bioreactor (sponge MBR) for recirculation of aquaculture wastewater in the Mekong delta, Vietnam. The performance of a sponge MBR with a moving-cube sponge medium (20% v/v) was evaluated at different hydraulic retention times (HRTs) for catfish pond wastewater treatment. The sponge MBR was operated at HRT values of 8, 4, and 2 h, which correspond to membrane fluxes of 5, 10, and 20 L/m2 per hour, respectively. The average total organic compounds (TOC) removal efficiencies were maintained at 93%, 94%, and 87% at an HRT of 8, 4, and 2 h, respectively, while the average total nitrogen (TN) removal efficiencies were 84%, 70%, and 57%. The TOC and TN removal efficiencies decreased with a decrease in HRT (increase in membrane flux). Permeate concentrations of TOC and TN were as low as 6.3 and 2.7mg/L at the operated HRTs, respectively. Compared to the conventional MBR, the sponge MBR had twice the TN removal capacity at the same HRT due to simultaneous nitrification–denitrification. In addition, the results implicated that the fouling rate (dTMP/dt) increased in an inverse proportion with HRT (h) according to the power equation (fouling rate = 4.2474 HRT- 2.225). Free movement of sponges in the reactor improved fouling due to sweeping of the cake layer on the membrane surface. Results reveal that the sponge MBR was effective in terms of simultaneous organic and nitrogen removal, fouling control, and water recirculation for catfish farm wastewater in the Mekong delta, Vietnam.

International Biodeterioration & Biodegradation, 2014

ABSTRACT This study shows high nitrogen removal efficiency of a combination of partial nitritatio... more ABSTRACT This study shows high nitrogen removal efficiency of a combination of partial nitritation and Anaerobic Ammonium Oxidation (anammox) process for old landfill leachate treatment. A lab-scale experiment including partial nitritation using a sequencing batch reactor (PN-SBR) followed by a anammox hybrid reactor (HAR), which consists of suspended biomass layer in the bottom part and bio-carrier bed in the upper part run at the influent total ammonia concentrations (TAN) of 500 mg N/L and 1000 mg N/L. The result of PN-SBR experiment showed that the NO2–N:NH4–N ratio achieved about 1.22 and 1.02 at HRT of 12 h (influent TAN of 500 mg N/L) and HRT of 19 h (influent TAN of 1000 mg N/L), respectively. Simultaneously, the HAR was operated at the nitrogen loading rate (NLR) of 4.2 and 8.3 kg N/m3.d, corresponding to influent TAN of 500 mg N/L and 1000 mg N/L, respectively. The effluent of the system containing 9.7 ± 3.5 mg NH4–N/L, 1.7 ± 0.4 mg NO2–N/L and 23 ± 4 mg NO3–N/L (equivalent to 35 ± 4 mg TN/L) at NLR of 1.02 for PN-SBR and NLR of 4.2 kg N/m3.d for HAR. This effluent quality was good enough to meet Vietnamese treated landfill leachate quality. The system obtained TN removals of 93 ± 1% and 81 ± 1.2% at NLRs of 4.2 kg TN/m3.d (phase I) and 8.3 kg TN/m3.d (phase II), respectively. The total biomass of HAR including attached biomass and suspended one was maintained up to 20,400 mgVSS/L at the end of the experiment when the removal rate of anamnox biomass obtained 0.4 kg TN/kgVSS.d. While, PN-SBR was kept at 2300 mg MLVSS/L and SRT of 10–12 days at NLR of 4.2 kg TN/m3.d, which the nitrogen conversion rate of AOB was 0.53 kg TAN/kgVSS.d. In terms of COD removal, it is found that PN-SBR removed only 14% of influent COD, whereas HAR removed 30% of COD.

Desalination and Water Treatment, 2014

ABSTRACT This study evaluated nutrients removal from domestic wastewater by five plants in wetlan... more ABSTRACT This study evaluated nutrients removal from domestic wastewater by five plants in wetland roof systems (WR). The study plants include Arachis duranensis (1), Evolvulus alsinoides (2), Cosmos Bipinnuatus (3), Cyperus alternifolius Linn (4), and Philodendron hastatum (5). The WRs were acclimatized at hydraulic loading rates (HLR) of 220m3/ha d and operated at HLR of 300m3/ha d. The plants (1), (2), (4), and (5) had the ability to grow under the rooftop conditions with domestic wastewater as a nutrient source while the plant (3) was not suitable and dead after 20 d of operation. Generally, A. duranensis (1) and C. alternifolius Linn (4) were the most suitable plants treating domestic wastewater under the conditions of WR. The average phosphorus removal efficiencies of (1) and (4) were approximately 75 and 89%, respectively, while the average nitrogen removal efficiencies were 69 and 92%. The phosphorus accumulation in plants (1) and (4) during operation was 20.4 and 29.4%, respectively, while the nitrogen accumulation was 21.5 and 93%. It is concluded that C. alternifolius Linn (4) has best nutrient removal among the study plants under the conditions of shallow bed WR treating domestic wastewater (24 ± 4 and 2.0 ± 0.4 kg TP/ha d).

Journal of Membrane Science, 2008

Aerobic granular sludge treatment system performs better than the conventional aerobic wastewater... more Aerobic granular sludge treatment system performs better than the conventional aerobic wastewater treatment in terms of treatability, strong microbial structure, high biomass retention and excellent settling ability. However, the effluent produced has high ...

International Journal of Waste Resources, 2013

ABSTRACT The objective of this study was to evaluate the performance and fouling behavior of memb... more ABSTRACT The objective of this study was to evaluate the performance and fouling behavior of membrane based septic tank (MBST).Woven Fiber Microfiltration (WFMF) introduced in the chamber of a septic tank as a submerged membrane for domestic wastewater treatment. Concentrations of black water stored in the third chamber were 125 ± 15 mg/L COD, 124 ± 28 mg/L SS and 59 ± 9 mg/L TKN. Results showed that COD removal was 54-78 % of which effluent achieved less than 50 mg/L. In addition, the withdrawal was mostly non-performed suspended solids. TMP level increased gradually, indicated low membrane fouling rate (dTMP/dt) of 0.4-1.0 kPa/day at flux as low as 2.5 LMH. While at the flux greater than 3.4 LMH the fouling rate increased rapidly with the fouling rate of 13 kPa/day. Keywords — membrane based septic tank; domestic wastewater; fouling; septic tank (ST); Woven Fiber Microfiltration (WFMF).