MBR System Research Articles

Membrane bioreactor for water reclamation in Singapore

The Public Utilities Board (PUB) of Singapore embarked on MBR technology evaluation program in 2002. The three systems, i.e. Zenon system, Mitsubishi system and Kubota system, were set up in early 2003 and evaluated. Other MBR systems like Memcor MBR, Toyoplus MBR, Singaport Cleanseas MBR, Huber MBR and Asahi MBR were tested later on or is under testing. These trials have generated valuable information on the design and operation of the MBR systems under tropical environment in pilot scales. PUB decided to extend the pilot scale operations by building a 23,000 m3/d demonstration plant at Ulu Pandan Water Reclamation Plant. This plant was commissioned in December 2006. The product of this plant is supplied to industries as Industrial Water. The plant produces industrial water which is superior to all the requirements. The power consumption is about 0.55 kwh/m3 and no intensive chemical cleaning has been done since the start-up of the plant for about 7 months.

Assessment of the reliability of an on-site MBR system for greywater treatment and the associated aesthetic and health risks

This study analyses the reliability of an on-site MBR system for greywater treatment and reuse. To achieve this goal simulation was performed based on the IWA ASM1 model which was adapted to describe biological and physical mechanisms for MBR greywater treatment based systems. Model results were found to agree well with experimental data from an on site pilot greywater treatment plant, after which the calibrated model was used in a Monte Carlo mode for generating statistical data on the MBR system performance under different scenarios of failures and inflow loads variations. Effluents quality and their associated risks were successfully estimated.

Evaluation of innovative operation concept for flat sheet MBR filtration system

One of the most limiting factors for the extension and acceptance of MBR filtration systems for municipal and industrial wastewater is the impact of membrane fouling on maintenance, operation and cleaning efforts. One field of action in the European Research Project "AMEDEUS" is the development and testing of MBR module concepts with innovative fouling-prevention technology from three European module manufacturers. This article deals with the performances of the flat-sheet modules by A3 Water Solutions GmbH in double-deck configuration evaluated over 10 months in Anjou Recherche under typical biological operation conditions for MBR systems (MLSS = 10 g/l; SRT = 25 days). By using a double-deck configuration, it is possible to operate with a net flux of 25.5 l/m2.h at 20 degrees C, a membrane air flow rate of 0.21 Nm3/h.m2 of membrane to achieve a stable permeability of around 500-600 l/m2.h.bar. Additionally, it was observed that it is possible to recover the membrane performance after biofouling during operation without intensive cleaning and to maintain stable permeability during peak flows. The evaluated concepts for equipping and operating MBR systems will be applied to several full-scale plants constructed by A3 Water Solutions GmbH.

Biomass adaptation to complex substrate degradation in membrane bioreactors: appropriated operating conditions

The aim of this work is to analyse the biological performances of two immersed membranes bioreactors focusing on the biomass adaptation to complex substrate degradation and the performance in term of permeate quality. Two influents were selected: a synthetic complex influent (acetate/Viandox, MBR1) and a real seafood processing wastewater (surimi product, MBR2). The MBR systems were operated for long periods without any sludge extraction except for sampling. Organic matter removal, sludge production and quality of the treated wastewater were analysed and studied. COD removal efficiencies after a period of biomass adaptation were higher than 97% and 95% for the synthetic and real wastewater respectively. In both cases, the COD of the treated wastewater was lower than 50 mg.L(-1). In spite of salt concentration in the real wastewater a biomass adaptation process occurs. In the overall operational period, a 0.058 gCOD P.gCOD T(-1) and a 0.12 gCOD P.gCOD T(-1) observed sludge yields were obtained for the MBR1 and MBR2 respectively. These values are approximately 5 to 10 times lower than those measured in conventional activated sludge process. These results showed that the presence of particular and some of non-easily degradable compounds in the influent of MBR2 didn't limit the performance of MBR in term of COD removal achieved. The results have also confirmed the excellent permeate quality for water reuse from MBRs systems.

Comparison of Biofoulants in BNR-MBR and Conventional MBR (C-MBR) Systems

Comparison of Biofoulants in BNR-MBR and Conventional MBR (C-MBR) Systems

Retrofitting Existing MBR Systems with Next Generation MBR Technology

Retrofitting Existing MBR Systems with Next Generation MBR Technology

Mbr System at the Nassau County WWTP

Mbr System at the Nassau County WWTP

Design and performance of BNR activated sludge systems with flat sheet membranes for solid-liquid separation

The use of immersed membranes for solid-liquid separation in biological nutrient removal activated sludge (BNRAS) systems was investigated at lab scale. Two laboratory-scale BNR activated sludge systems were run in parallel, one a MBR system and the other a conventional system with secondary settling tanks. Both systems were in 3 reactor anaerobic, anoxic, aerobic UCT configurations. The systems were set up to have, as far as possible, identical design parameters such as reactor mass fractions, recycles and sludge age. Differences were the influent flow and total reactor volumes, and the higher reactor concentrations in the MBR system. The performances of the two systems were extensively monitored and compared to identify and quantify the influence of the membranes on system response. The MBR UCT system exhibited COD, FSA, TKN, TP and TSS removals that were consistently equivalent or superior to the conventional system. Better P removal in the MBR was attributed to lower observed P uptake in the anoxic zone. High nitrate loads to the anoxic reactor appeared to be the determining factor in stimulating P uptake. The MBR UCT system had a greater sludge production than the conventional system. This was partly attributable to the retention of all solids in the MBR reactor. For steady state design this increase is accommodated by increasing the influent unbiodegradable particulate COD fraction. Additionally an attempt was made to determine the Alpha values in the oxygen transfer rate. This paper briefly summarises and compares the results from both systems, and the conclusions that can be drawn from these results.

Model-based optimisation of the biological performance of a sidestream MBR

A model-based optimisation of the operation in view of the biological performance in terms of nitrogen (N) and phosphorus (P) removal of a pilot-scale side-stream MBR has been performed by means of a two-tier scenario analysis. The methodology uses two different scenario analyses to simulate the effect of three degrees of freedom in the MBR system: (1) DO set-point in the aerobic reactor, (2) sludge residence time and (3) internal recirculation rate. The scenarios are simulated using a calibrated ASM2d MBR model. Effluent quality, in terms of nitrate, ammonia and phosphate, is used to select the best scenario. It proved to be a compromise between nitrogen and phosphorus removal as these are linked. A 42% reduction in ammonium and a 32% reduction in nitrate concentration were achieved. Phosphate removal is partly sacrificed (39% increase) compared to the standard operation.

Development of a continuous protein and polysaccharide measurement method by Sequential Injection Analysis for application in membrane bioreactor systems

Polysaccharides and proteins are the main components of extracellular polymeric substances, which are considered to give a major contribution to the overall fouling potential of the MBR system. This work focuses on the automation of spectrophotometrical assays for protein and polysaccharide determination for on-line measurement in MBR. Sequential Injection Analysis (SIA) was identified as more suitable for continuous measurements. In screening tests the selection of an appropriate assay for the successful automation by means of SIA was carried out. Lowry Assay and Dubois Assay were chosen for protein and polysaccharide determination. Lowry Assay could be successfully automated by means of SIA. The automated method shows a lower sensitivity than the manual Lowry method, what can be contributed to specific characteristic of SIA. The confidence limit was calculated to 2.8 mg/L. The automated method shows in validation tests good correspondence with protein concentrations measured with the manual assay (R(2)=0.971). The successful establishment of the Dubois Assay for polysaccharides failed so far due to sensitivity problems.

Use of membrane bioreactors for the bioremediation of chlorinated compounds polluted groundwater

Chlorinated compounds are widely used in agricultural applications where they are employed as components of pesticides; this leads often to pollution of groundwater near to agricultural sites, with serious effects for human health. The aim of the present study was the development of a membrane bioreactor, a new and effective water treatment technology, for the bioremediation of water polluted by 1,2-dichloroethane, 1,2-dichlorobenzene and 2-chlorophenol. Before starting-up the MBR system, a biomass was acclimated, to simultaneously degrade the three chlorinated compounds; then the acclimated biomass was inoculated into the MBR. The results showed a higher removal rate for 1,2-dichloroethane than for 1,2-dichlorobenzene; besides, the presence of 1,2-dichlorobenzene together with 1,2-dichloroethane decreased 1,2-dichloroethane specific removal rate. 2-chlorophenol was degraded only in presence of phenol as co-substrate, and the presence of phenol and 2-chlorophenol decreased 1,2-dichloroethane specific removal rate of approximately eight times, while 1,2-dichlorobenzene specific removal rate was not affected.

Removal of native coliphages and coliform bacteria from municipal wastewater by various wastewater treatment processes: Implications to water reuse

The efficacy of a conventional activated sludge wastewater treatment process and the membrane bioreactor technology in removing microbial pathogens was investigated. Total and fecal coliforms and somatic and F-specific coliphages were used as indicators of pathogenic bacteria and viruses. Up to 5.7 logs removal of coliforms and 5.5 logs of coliphages were observed in the conventional treatment process with advanced tertiary treatment. Addition of chemical coagulants seemed to improve the efficacy of primary and secondary treatment for microorganism removal. Complete removal of fecal coliforms and up to 5.8 logs removal of coliphages was observed in the MBR system. It was shown that the MBR system was capable of high removal of coliphages despite the variation in feed coliphage concentrations. The results of this study indicated that the MBR system can achieve better microbial removal in far fewer steps than the conventional activated sludge process with advanced tertiary treatment. The final effluent from either treatment processes can be potentially reused.

NITRITE EFFECT ON THE PHOSPHORUS UPTAKE ACTIVITY OF PHOSPHATE ACCUMULATING ORGANISMS (PAO) IN PILOT-SCALE SBR AND MBR REACTORS

NITRITE EFFECT ON THE PHOSPHORUS UPTAKE ACTIVITY OF PHOSPHATE ACCUMULATING ORGANISMS (PAO) IN PILOT-SCALE SBR AND MBR REACTORSBatch tests, performed to investigate the effect of nitrite on the P-uptake activity of biomass grown in pilot-scale SBR and MBR systems, showed that the nitrite has an inhibitory but reversible effect on the aerobic P-uptake activities of the SBR and the MBR biomass. The inhibitory effect was found more pronounced on the SBR biomass, in which the aerobic Puptake was inhibited by 65 % and 37 % at...Author(s)Gürkan SinKwinten NivilleGiulia BachisTao JiangIngmar NopensStijn Van HullePeter A. VanrolleghemSourceProceedings of the Water Environment FederationSubjectSession 1: Biological Phosphorus RemovalDocument typeConference PaperPublisherWater Environment FederationPrint publication date Jan, 2007ISSN1938-6478SICI1938-6478(20070101)2007:2L.17;1-DOI10.2175/193864707787976803Volume / Issue2007 / 2Content sourceNutrient Removal and Recovery SymposiumFirst / last page(s)17 - 38Copyright2007Word count225

Thermal and conductometric studies of the CeBr 3–MBr binary systems (M = Li, Na)

DSC was used to investigate phase equilibrium in the CeBr 3–MBr (M = Li, Na) systems. They represent typical examples of simple eutectic systems. The eutectic composition and eutectic temperature, x(CeBr 3) = 0.249, T eut = 709 K and x(CeBr 3) = 0.372, T eut = 692 K, were found for CeBr 3–LiBr and CeBr 3–NaBr systems, respectively. The electrical conductivity of CeBr 3–MBr liquid mixtures, together with that of pure components was measured down to temperatures below solidification. Results obtained are discussed in term of possible complex formation.

Air lift relevance in a side-stream MBR system

Nowadays, two main MBR configurations are developed in wastewater treatment (Fig. 1a and b). The former is based on a side stream membrane module position, it is generally developed for the industrial wastewater treatment because of its compactness even if it requires more energy due to the necessity of using high suspension flow rate recycles throughout the membrane module to minimise fouling rates [1]. With this configuration the membrane maintenance is easy because of the side stream position of the membrane module relatively to the bioreactor. The second configuration is based on the immersion of membrane module directly inside the bioreactor. This configuration is more extensive because of functioning under low transmembrane pressure, TMP, and also requires low energy requirement because of using air fluid as turbulence supply [2]. Nevertheless, when some drastic membrane fouling or module clogging occurs, the cleaning protocol obliges to more difficult maintenance [3]. 2. Theory and experimental

Membrane bioreactor application in wastewater re-use from the effluent of Bali primary WWTP, northern Taiwan

Two MBR pilot systems were constructed and tested in the Bali Primary WWTP. The pilot study shows that two MBR systems, i.e. the Green-MenBio system (MBR-1) and the Bio-MF system (MBR-2), can both fulfill the requirement of wastewater reclamation standard. The MBR-2 system is more economical compared with MBR-1 system. The cost of US dollars 0.10-0.16/m3 is estimated to reclaim the effluent of primary WWTP in Taiwan. The Bali Primary WWTP has the capacity of 1,320,000 cmd which is the biggest in Taiwan. The domestic wastewater of partial Taipei City and Taipei County are collected and transported to the Bali Primary WWTP. The effluent of the Bali Primary WWTP is then discharged into the ocean through two 3.8 m marine outfalls. The AO processes are installed in both MBR systems. More than 90% of the NH3-N can be removed through the AO and membrane processes. The outflow of the MBR systems (without RO) can reach the quality of COD <30 mg/l, BOD <10 mg/l, SS <5 mg/l, NH3-N <3 mg/L. The outflow of the MBR system is proposed to transport 40 km south to the Taoyuan County where four new industrial parks are to be constructed. Part of the reclaimed water is to be used on irrigation and another portion is to be sent to the industries after RO treatment.

Removal of inhibitory phenolic compounds by biological activated carbon coupled membrane bioreactor

Phenolic compounds cause problems for conventional treatments due to their toxic and inhibitory properties. This work investigated the treatability of phenolic compounds by using two membrane-bioreactor systems, namely: activated sludge coupled with MBR (AS-MBR) and biological granular activated carbon coupled with MBR (BAC-MBR). Initially, the system was fed with phenol (500 mg/L) followed by adding 2,4-dichlorophenol (2,4-DCP). Phenol, 2,4-DCP, TOC and COD removal were higher than 98.99% when the organic load ranged between 1.80 and 5.76 kg/m3.d COD. In addition to MBR system development, removal mechanisms were also investigated. Relatively low values of phenol adsorption of GAC and biomass, and high maximum substrate removal rates obtained from a biokinetic experiment, proved that the removals were mainly due to biodegradation. Analysis of sludge indicated a significant difference in the sludge characteristics of the two reactors. The high EPS content in BAC-MBR led to higher viscosity and poor sludge settling properties. The relationship between sludge properties and EPS components revealed that settleability had no direct correlation with EPS, though it was better correlated to protein/carbohydrate ratios.

Economic feasibility of on-site greywater reuse in multi-storey buildings

This paper analyses the economic feasibility of on-site greywater reuse in the urban sector. RBC- and MBR-based systems were selected as model systems for the economic analysis. The analysis showed that the investment costs of an RBC-based system consist of less than 0.5% of the price of a flat for buildings of more than 20 flats (five storeys). At a water price of 1.16 US$/m 3 and sewage charges of 0.3 US$/m 3, the RBC-based system became economically feasible when the building size reached seven storeys (28 flats). The on-site MBR-based system proved to be economically unrealistic, becoming economically feasible only when the building size exceeded 40 storeys. Cluster MBR-based systems, incorporating several buildings together, became feasible when the cluster size was four buildings or more (each 10 storeys high). A subsidy of 0.7 US$/m 3 reused resulted in much smaller systems becoming economically feasible: four-storey buildings (16 flats) for the RBC system and two buildings for the cluster MBR system. The on-site MBR system (single building) remained unfeasible.

A combined VSEP and membrane bioreactor system

In a MBR system, huge amount of solid suspension clogged the membrane and reduced the permeate flux. Mechanical motions were believed to be effective in preventing premature clogging of the membrane. Three different mechanical motions; namely cross oscillation, lengthwise oscillation and the VSEP were investigated. The VSEP combined mechanical motion and the high trans-membrane pressure achieved the best GFD for MBR membrane filtration.

Treatment of synthetic wastewater by a novel MBR with granular sludge developed for controlling membrane fouling

A novel membrane bioreactor system, a membrane bioreactor with aerobic granular sludge (MGSBR), was developed to treat municipal wastewater in this paper. The main goal was to control the membrane fouling by changing the configuration of aerobic sludge, also to examine the feasibility of the MGSBR used to treat wastewater. The results in the paper demonstrated that treatment performance of a MGSBR was stable and on a high level. The ranges of COD degradation and concentration in the effluent from a MGSBR were 80–95% and 15–50 mg L −1, respectively, during the period of operation examined. Compared with the conventional MBR (MFSBR) system, anaerobic environment in a MGSBR system could be effectively provided inside aerobic granules, which benefited for the denitrification of nitrate nitrogen. The NH 4–N concentration in effluent from the MGSBR system was all the time lower than 15 mg L −1. During the examined time, the membrane permeability of MGSBR was more 50% higher than that of a MFSBR. The substitute of floc sludge by aerobic granules in the MBR system benefited for controlling flux decline and membrane fouling with good performance of treatment. The supernatant (colloids + solutes) was almost the controller of the membrane flux in a MGSBR. The cleaning recovery of hydraulic cleaning in membrane flux from the MGSBR was 87.7%, which was near 10% lower than that of MFSBR system. However, the chemical cleaning could remove most of foulants on the membrane surface and within the pores with the recovery of near 100%. As a novel MBR system possessing advantages in controlling of membrane fouling with good performance of wastewater treatment, the MGSBR process deserved more attention and deep investigation in the future.