MBR Process Research Articles

가압식 분리막을 이용한 Side-Stream MBR 공정의 비정상 운전조건에서 막 오염 저감

가압식 분리막을 이용한 Side-Stream MBR 공정의 비정상 운전조건에서 막 오염 저감

Treatment of cosmetic effluent in different configurations of ceramic UF membrane based bioreactor: Toxicity evaluation of the untreated and treated wastewater using catfish (Heteropneustes fossilis).

Extensive usage of pharmaceutical and personal care products (PPCPs) and their discharge through domestic sewage have been recently recognized as a new generation environmental concern which deserves more scientific attention over the classical environmental pollutants. The major issues of this type of effluent addressed in this study were its colour, triclosan and anionic surfactant (SDS) content. Samples of cosmetic effluent were collected from different beauty treatment salons and spas in and around Kolkata, India and treated in bioreactors containing a bacterial consortium isolated from activated sludge samples collected from a common effluent treatment plant. Members of the consortium were isolated and identified as Klebsiella sp., Pseudomonas sp., Salmonella sp. and Comamonas sp. The biotreated effluent was subjected to ultrafiltration (UF) involving indigenously prepared ceramic membranes in both side-stream and submerged mode. Analysis of the MBR treated effluent revealed 99.22%, 98.56% and 99.74% removal of colour, triclosan and surfactant respectively. Investigation of probable acute and chronic cyto-genotoxic potential of the untreated and treated effluents along with their possible participation in triggering oxidative stress was carried out with Heteropneustes fossilis (Bloch). Comet formation recorded in both liver and gill cells and micronucleus count in peripheral erythrocytes of individuals exposed to untreated effluent increased with duration of exposure and was significantly higher than those treated with UF permeates which in turn neared control levels. Results of this study revealed successful application of the isolated bacterial consortium in MBR process for efficient detoxification of cosmetic effluent thereby conferring the same suitable for discharge and/or reuse.

Fractionation, characterization and C-, N-disinfection byproduct formation of soluble microbial products in MBR processes

Soluble microbial products are heterogeneous organic materials generated during microbial growth and decay, which are the major soluble organic matters in MBR effluents and are the primary precursors forming disinfection by-products (DBPs). In this study, biomass associated products (BAP) and utilization associated products (UAP) were separately produced to investigate their physical chemical characteristics and disinfection byproduct (DBP) formation during chlorination in the presence of ammonia. BAP had higher formation reactivity of halogenated carbonaceous and nitrogenous DBPs including trihalomethanes, haloketones, haloacetonitriles and trichloronitromethane due to their higher percentage of large molecular weight (MW) materials and humic substances compared with UAP. However, the nonhalogenated species N-nitrosodimethylamine (NDMA) yield of UAP was twice higher than that of BAP because UAP contained more nitrogenous organic matters with MW<500Da including aromatic polypeptide/amino acid-like materials and secondary amines, which have been proved to have high NDMA formation potential.

유기물 제어를 통해 분리막의 fouling을 저감시키는 MBR 공정개발

유기물 제어를 통해 분리막의 fouling을 저감시키는 MBR 공정개발

Treatment of reverse osmosis concentrate by electrolysis and MBR process

In this study, the reverse osmosis (RO) concentrate treatment technology, which combines the electrolysis process with the MBR process, has been suggested to treat the RO concentrate generated in the water recycle process, which applied the RO membrane. The electrolysis process constructed in this study is to reduce the MBR process load by removing the non-degradable matters and the nitrogen compound, which are the weakness of biological treatment. When treating the RO concentrate through the electrolysis, the disinfection by-products—like residual chlorine, THMs and so forth—are generated. Since this reaction of the by-products affects the microbes, PAC was injected within the MBR reactor to desalinate the treated water. As the MBR process shows considerably high treatment efficiency for the organic matters and can increase the concentration of the activated sludge within reactor, it is effective to treat the nitrogen and phosphorus, which cause the eutrophication of water, but since there is a limit in treating the RO concentrate with this single process, such a hybrid process was suggested. The comparative experiment was performed depending on whether the electrolysis-applying pretreatment of RO concentrate has been applied or not, and whether the PAC has been injected within MBR or not. As a result, the DOC, T-N and T-P removal efficiency of the suggested process was each approximately 98.0, 40.0 and 45.6%, respectively. The experiment results showed that the suggested process has great potential in RO concentrate treatment.

Mechanisms of pathogenic virus removal in a full-scale membrane bioreactor.

Four pathogenic virus removal mechanisms were investigated in a full-scale membrane bioreactor (MBR; nominal pore size 0.04 μm): (i) attachment of virus to mixed liquor solids; (ii) virus retention by a just backwashed membrane; (iii) virus retention by the membrane cake layer; and (iv) inactivation. We quantified adenovirus, norovirus genogroup II (GII), and F+ coliphage in the influent wastewater, the solid and liquid fractions of the mixed liquor, return flow, and permeate using quantitative PCR (adenovirus and norovirus GII) and infectivity assays (F+ coliphage). Permeate samples were collected 4-5 days, 1 day, 3 h, and immediately after chlorine enhanced backwashes. The MBR achieved high log removals for adenovirus (3.9 to 5.5), norovirus GII (4.6 to 5.7), and F+ coliphage (5.4 to 7.1). The greatest contribution to total removal was provided by the backwashed membrane, followed by inactivation, the cake layer, and attachment to solids. Increases in turbidity and particle counts after backwashes indicated potential breakthrough of particles, but virus removal following backwashes was still high. This study demonstrates the ability of the MBR process to provide over 4 logs of removal for adenovirus and norovirus GII, even after a partial loss of the cake layer, and provides evidence for assigning virus disinfection credit to similar MBRs used to reclaim wastewater for reuse.

Hydrolytic acidification via rumen microorganisms and aerobic MBR to reduce contaminants in pulping midcourse wastewater

Experiments on microbial degradation with hydrolytic acidification–aerobic (membrane bioreactor) MBR process were conducted to treat the pulping midcourse wastewater (PMW) with chemical oxygen demand (COD) concentration of 1,182 mg/L, chromaticity of 327 PCU, and TSS concentration of 153 mg/L. Rumen micro-organisms (RM) were used in the hydrolytic acidification process. The experimental results demonstrated that the hydrolytic–aerobic process could raise the biodegradability of the PMW, the VFA concentration could reach 200 mg/L, and the acidification rate was 24%; the effluent COD could reach 96 mg/L, the chromaticity 80 PCU, and the TSS 15 mg/L. These results suggested that hydrolytic acidification via RM and aerobic MBR could be a promising way for effective disposal of puling midcourse wastewater.

Quorum Sensing 制御を利用したMBRにおける バイオフィルム形成抑制技術の開発

The activated sludge system and MBR are the main and highly developed processes for the wastewater treatment. Biofouling and biofilm formation are big problems on MBR processes and the solution technologies against them are strongly sought. Recently, the relation between a biofilm formation and a microbial communication system has been elucidated. Microbes can communicate each other with some kinds of signal compounds and regulate their activities with these communication systems. Quorum sensing is one of the bacterial cell–to–cell communication mechanisms depending on cell population density. As bacteria regulate biofilm formation through quorum sensing, the inhibition methods of quorum sensing seem to be useful to inhibit the biofilm formation. We report here about the several techniques of the quorum sensing control methods and the applications of these techniques to inhibit biofilm formation.

Ultraviolet membrane bioreactor for enhancing the removal of organic matter in micro-polluted water

This research investigated the organic matter removal performance using an ultraviolet (UV) treatment membrane bioreactor (UV–MBR) in micro-polluted surface water. Compared with a conventional MBR process, the UV–MBR achieved higher removal efficiencies in terms of the reduction of CODMn and UV254, which were reduced by 58 and 63%, respectively. The organic matter removal rate increased significantly arising from biodegradation mechanisms. Furthermore, the ammonia nitrogen and nitrite nitrogen were removed almost completely and not affected by the subsequent UV treatment. Through the UV treatment, a fraction of refractory organics was transformed into biodegradable organics available to the microbial consortium in the reactor. UV treatment of the raw water leads to an increase of BDOC content from 0.22 to 0.88 mg L−1 after 5 d inoculation. According to the analysis of the characteristics of hydrophobic/hydrophilic compounds, the relative molecular weight distribution and the fluorescence excitation–emission matrix of the organics, it can be indicated that the organics were transformed into biodegradable organics because part of molecules were split into simple structures during the UV treating process. Furthermore, the organics removed by the UV–MBR were hydrophobic fractions.

Discussion on MBR Treatment Process of Domestic Landfill Leachate Design Issues in Northeast Area

MBR technology has been widely used in northeast China's leachate treatment projection for its obvious technical advantages. However, the complex nature of the Northeast leachate as well as relatively more calculations design of MBR process, became the key to the success of the project. This article in view of the present our country MBR treatment process of domestic refuse landfill leachate treatment of some design problems and puts forward some personal views and suggestions,, for example the MBR process calculation method of reference.

Performance of an innovative step-feed An-M(A/O)-MBR process for nutrients removal

An innovative process step-feed Anaerobic-multiple Anoxic/Oxic-Membrane Bioreactor [An-M(A/O)-MBR] was developed for biological phosphorus and nitrogen removal from synthetic domestic wastewater. This process was composed of an anaerobic reactor, a multiple phases of aerobic and anoxic zones (multiple A/O zone) in sequence followed by a continuous aerated MBR. Performance of the laboratory-scale system was investigated at different organic compounds in the influent. The results showed that, under the conditions imposed, although the Chemical Oxygen Demand (COD) concentration fluctuated in the range of 120–1,200 mg/L, high performance on COD removal was achieved in the system and more than 95% removal efficiency was obtained throughout the operation, the COD concentrations in the effluent were lower than 50 mg/L throughout the operation. However, COD levels in the influent had great influence on nitrogen and phosphorus removal. When COD level was low (120–200 mg/L), poor performance of nitrogen and phosphorus removal were obtained because of carbon source deficiency. Good performance on total nitrogen (TN) and total phosphorus (TP) removal were achieved when COD level was in the range of 350–710 mg/L, and the average removal efficiency of TN and TP was above 85 and 84%, respectively. But when COD increased to a high level (1,110–1,200 mg/L), the performance of nitrogen and phosphorus removal also deteriorated possibly because of the shift of the composition of the microbial communities.

Sewage Treatment Plant Reconstruction Project Design at Cold Area in the Northeast of China

Sewage treatment plant reconstruction project in cold area of China (the scale of processing is 20×104m3/d). The project have adopted advanced MBR process for both lacking space and improving effluent quality requirements .After secondary treatment, sewage flow through invasive hollow fiber membrane module to dewater, and then discharged the water after chlorination. Relatively, designed effluent quality is stable and achieve the primary standard of " comprehensively discharged standard of sewage in Liaoning province" (DB21/1627-2008). This paper introduced the technological process and main structure design parameters, the maintenance of membrane module as well as economic and environmental benefits analysis and so on of the sewage treatment plant.

암모니아 센서를 이용한 간헐폭기 Membrane bioreactor공정에서의 전력비 저감과 관형막을 이용한 슬러지 농축에 관한 연구

It is essential to decrease energy consumption and excess sludge to economically operate sewage treatment plant. This becomes more important along with a ban on sea dumping and exhaustion of resource. Therefore, many researchers have been study on energy consumption reduction and strategies for minimization of excess sludge production from the activated sludge process. The aeration cost account for a high proportion of maintenance cost because sufficient air is necessary to keep nitrifying bacteria activity of which the oxygen affinity is inferior to that of heterotrophic bacteria. Also, additional costs are incurred to stabilize excess sludge and decrease the volume of sludge. There were anoxic, aerobic, membrane, deairation and concentration zone in this MBR process. Continuous aeration was provided to prevent membrane fouling in membrane zone and intermittent aeration was provided in aerobic zone through ammonia sensor. So, there was the minimum oxygen to remove below limited quantity that could be eliminated in membrane zone. As the result of this control, energy consumption of aeration system declined by between 10.4 % and 19.1 %. Besides, we could maintain high MLSS concentration in concentration zone and this induced the microorganisms to be in starved condition. Consequentially, the amount of excess sludge decrease by about 15 %.

Lessons learned during startup, testing and optimization of membrane bioreactors systems for enhanced nutrient removal

Membrane bioreactors are known for producing high quality effluent from wastewater treatment facilities in order to meet stringent regulatory requirements (Fleischer et al. 2005), accommodate growth (Vadiveloo &amp; Cisterna 2008), provide opportunities for water reuse (Schmidt et al. 2011), and achieve other operational goals for various municipalities, utilities and industries (Cummings &amp; Frenkel 2008). The process of testing, starting up and optimizing an MBR process for enhanced nutrient removal at the end of a construction project is often overlooked. Even a well-designed MBR can fail to meet expectations if the system is not properly configured during the startup phase, making this a critical step in any successful implementation of membrane technology. The startup phase of two municipal MBR plants were compared to demonstrate the importance of various strategies for initial process optimization, with a focus on lessons learned, techniques and performance expectations that can be applied to future projects.

Technical Evaluation of MBR Process for the Wastewater Treatment of Beverage Fabrication Processes

Technical Evaluation of MBR Process for the Wastewater Treatment of Beverage Fabrication Processes

Monitoring and examination of adaptation period of microorganisms in membrane-bioreactor system treating fruit juice industry wastewaters

In this study, fruit juice industry wastewaters by using MBR process have been monitored and examined considering effective microorganisms and changes in biodiversity during the treatment period. Microbiological examinations have been carried out using conventional microbiological methods and microscopic observations. Eukaryotic and prokaryotic microorganisms and also floc structure of the activated sludge were identified and characterised. On the other hand, environmental parameters effective on microbial diversity of MBR process treating fruit juice wastewaters have been identified and discussed. Fruit juice wastewaters supported almost all kinds of microorganisms, primarily filamentous fungi Aspergillusspp., and ciliated protozoa Coccidiaspp. and eliminated nematodes from the MBR system.

Municipal wastewater reclamation and reuse in the leather industry

In the present work, an integrated pilot-scale membrane system (membrane bioreactor–nanofiltration [MBR–NF]) was applied to the treatment of municipal wastewater to produce reclaimed water. Its performance was evaluated and designed to meet the requirements of the water quality to use in the tanning process. The feasibility of using reclaimed wastewater in the different wet phases of the tanning process (beamhouse, tanning, re-tanning, dyeing, and fatliquoring) was investigated on a pilot scale for manufacturing chrome-tanned leathers. The results showed that the combination of MBR and NF processes applied to municipal wastewaters was adequate for recovering water with low hardness, very low Fe, Mn, and ammonium levels as required by tanneries. The pilot-scale tanning tests demonstrated that there were no significant differences between the wet-blue (chrome-tanned) leathers produced using treated wastewater and those produced using softened tap water in terms of physical and sensorial properties. Hence, the suitability of the treated water for use in the tanning was verified and validated.

Tracing biofouling to the structure of the microbial community and its metabolic products: A study of the three-stage MBR process

The biofouling characteristics of a sequential anoxic/aerobic-membrane bioreactor (A/O MBR) were analyzed during the three-stage process (fast-slow-fast transmembrane pressure (TMP) increasing). The results indicated: during the stage 1 (before day 1), the microbial communities in the activated sludge (AS), cake sludge (CS) and biofilm (BF) were similar to each other, and the adsorption of microbes and the metabolic products was the main factor that led to TMP increase; during the stage 2 (between day 1 and day 7), the cake layer begun to form and the TMP continued to rise gradually at a reduced rate compared to stage 1, at this point a characteristic microbial community colonized the CS with microorganisms such as Saprospiraceae and Comamonadaceae thriving on the membrane surface (BF) probably due to greater nutrient availability, and the predominance of these species in the microbial population led to the accumulation of biofouling metabolic products in the CS, which resulted in membrane fouling and the associated rise in TMP; during the final stage (after day 7), the biofilm had matured, and the activity of anaerobes stimulated cake compaction. The statistical analysis showed a correlation between the TMP changing rate and the carbonhydrates of soluble microbial products (SMPc) content in the CS. When the SMPc concentration rose slowly there was a low level of biofouling. However, when the SMPc accumulating rate was greater, it resulted in the more severe biofouling associated with the TMP jump. Furthermore, the correlation coefficient for the TMP increase and protein concentrations of extracellular polymeric substances (EPSp) in the CS was highly significant. The cluster analysis suggested that the AS microbial community remained stable during the three TMP change stages, while the CS and BF community were changed accompanied with the TMP change. The interaction between the microbial communities and the metabolic products lead to the significant correlation between them. The EPSp in conjunction with the SMPc were the main factors that accelerate the membrane fouling. The rapid rise of SMPc triggered a sudden increase in the TMP, while the accumulation of EPSp caused the sustained rise in TMP.

Nutrient removal performance and microbial community analysis of a combined ABR–MBR (CAMBR) process

In order to reduce the external nutrient loads in Lake Taihu, it was found that controlling nutrient input is the most effective way of reducing the risk of blooms. In this regard, nutrient removal by using a combined process consisting of an anaerobic baffled reactor and an aerobic membrane bioreactor for municipal wastewater treatment was investigated. The results demonstrated that hydraulic retention time, recycle ratio and dissolved oxygen had a negligible effect on the removal efficiencies of chemical oxygen demand and ammonia. Optimal operation conditions with a hydraulic retention time of 7.5h at a recycle ratio of 200% and dissolved oxygen of 3mg/L was shown to achieve higher quality effluent with chemical oxygen demand, ammonium, total nitrogen and total phosphorus of 26, 0.5, 10.5 and 0.4mg/L, respectively. Analysis of fluorescence in situ hybridization showed that the specialized microorganisms, including nitrifying bacteria (ammonia-oxidizing bacteria and nitrite-oxidizing bacteria), and phosphorus accumulating organisms, were enriched in this process. The profile of nitrite-oxidizing bacteria was similar to that of ammonia-oxidizing bacteria. The nitrifying bacterial population had a good correlation with nitrogen removal efficiency. A good correlation was also observed between phosphorus removal performance and the percentage of phosphorus accumulating organisms present in the sludge.

하수재이용 공정에서 발생되는 RO농축수 처리를 위한 MBR 공정 적용

하수재이용 공정에서 발생되는 RO농축수 처리를 위한 MBR 공정 적용