• Membrane and Water Treatment
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• v.11 no.1
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• pp.31-39
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• 2020

Anaerobic membrane bioreactor (AnMBR) treatment has been widely studied in recent years because of the potential for production of bio-energy from wastewater and energy-positive operation of wastewater treatment plants. Several AnMBR systems, including those that incorporate ceramic membranes, take advantage of enhanced water permeability and low membrane fouling potentials. Given that differences in the ceramic membranes may influence the results of AnMBR studies, relevant details are discussed in this review, which focuses on the profiles of common ceramic membranes used in AnMBR, treatment and filtration performances of different anaerobic ceramic membrane bioreactors (AnCMBRs), and the membrane fouling mitigation methods available for effective AnCMBRs operation. The aim of this review is to provide a comprehensive summary of AnCMBR performance, feed wastewater characteristics, operating conditions, and the methods available for effective fouling mitigation.

• Biotechnology and Bioprocess Engineering:BBE
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• v.7 no.5
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• pp.289-294
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• 2002

Cellulose production by Acetobacter pasteurianus was investigated in static culture using four bioreactors with silicone rubber membrane submerged in the medium. The shape of the membrane was flat sheet, flat sack, tube and cylindrical balloon. Production rate of cellulose as well as its yield on consumed glucose by the bacteria grown on the flat type membranes was approximately ten-fold greater than those on the non-flat ones in spite of the same membrane thickness. The membrane reactor using flat sacks of silicone rubber membrane as support of bacterial pellicle can supply greater ratio of surface to volume than a conventional liquid surface culture and is promising for industrial production of bacterial cellulose in large scale.

• Microbiology and Biotechnology Letters
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• v.17 no.6
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• pp.624-628
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• 1989

A study on the citric acid production using Saccharomycopsis lipolytica (NRRL Y7576) was carried out in shake-flasks, air-lift and membrane recycle bioreactors. The cells entrapped in Ca-alginate beads were used in shake-flasks and air-lift reactor. Repeated batch fermentation in shake-flasks was successfully performed for 34 days and resulted in a yield of 54%. Increased yield (63%) was obtained in the air-lift reactor operation using nitrogen deficient medium (NDM). In the membrane recycle bioreactor operation, the maximal dry cell mass concentration was 39 g/1 at a dilution rate of 0.02 h$^{-1}$ and the yield with NDM was higher than that with growth medium. In addition, the yield and volumetric productivity with pure oxygen supply were greatly improved compared with those with air supply.

• Membrane and Water Treatment
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• v.3 no.1
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• pp.1-23
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• 2012

The coupling of anaerobic biological process and membrane separation could provide excellent suspended solids removal and better biomass retention for wastewater treatment. This coupling improves the biological treatment process while allowing for the recovery of energy through biogas. This review gives a basic description of the anaerobic wastewater treatment process, summarizes the state of the art of anaerobic membrane bioreactors (AnMBRs), and describes the current research trends and needs for the development of AnMBRs. The research interest on AnMBR has grown over the conventional anaerobic processes such as upflow anaerobic sludge blanket (UASB). Studies on AnMBRs have developed different reactor configurations to enhance performances. The AnMBR performances have achieved comparable status to other high rate anaerobic reactors. AnMBR is highly suitable for application with thermophilic anaerobic process to enhance performances. Studies indicate that the applications of AnMBR are not only limited to the high strength industrial wastewater treatment, but also for the municipal wastewater treatment. In recent years, there is a significant progress in the membrane fouling studies, which is a major concern in AnMBR application.

• Proceedings of the Membrane Society of Korea Conference
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• 2003.07a
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• pp.7-10
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• 2003

Factors affecting filtration performance were investigated in a Sequencing Batch Reactor (SBR) coupled with a submerged microfiltration module. Special bioreactors for aerobic and anoxic phases, respectively, were specifically designed in order to differentiate tile effect of Dissolved oxygen (DO) from that of mixing intensity on membrane filterability. DO concentration as well as mixing intensity proved to have a major influence on the membrane performance regardless of the SBR phase. A higher DO concentration resulted in a slower rise in TMP, corresponding to less membrane fouling.

• Membrane Journal
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• v.25 no.3
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• pp.276-286
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• 2015

The effects of relaxation and backwashing on fouling in ultrafiltration were investigated using full-scale membrane bioreactors (MBRs) which operated at a constant flux of 30 LMH. This paper also estimated the feasibility of using intermittent aeration strategies for minimizing the hydraulic resistance to filtration in comparison with the continuous aeration for running MBRs. Multiple cycles of filtration (14.5 min each) and relaxation (0.5 min each) were repeated. Similarly, a backwash was conducted by replacing a relaxation after each filtration cycle for the comparative performance test. The attached cake thickness on the membrane rapidly increased, caused by subsequent no aeration leading to easier combining with gel layer and the formation of heterogeneous layer on the membrane surface. During periodic backwashing, it is expected that gel and thin cake layer might sufficiently be removed by heterogeneous layer. After periodic backwashing, subsequent cake layer formation during time of no aeration was rapid than frequent no aeration, acting as a prefilter and preventing further irreversible fouling. Based on the Pearson correlation analysis, overall period fouling (dTMP/min) and average of all cycles (dTMP/min) were strongly correlated with the on-off period of aeration for operating MBRs.

• Membrane Journal
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• v.33 no.6
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• pp.269-278
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• 2023

Enzyme Immobilized Membrane Bioreactors (EMBRs) are a novel method to treat dyes within wastewater. Due to their efficacy and high resistance to the environment, there has been a large amount of research being done in this area. There are a variety of ways to approach EMBRs that include both the enzyme itself and the structure of said enzymes. The bioreactor itself can be modified to suit the needs of the dye removal. Ranging from Enzymatic bioreactors to utilizing nanostructures such as graphene oxide or carbon nanotubes. Furthermore, nanoparticles such as TiO₂ can be used to enhance the EMBR further as well. The polymer-based membrane supporting structure also includes a variety of different ways to approach the problem of increasing efficacy. As seen, during the past decades, different approaches to this issue that utilize EMBRs have been done. This review aims to summarize the methodologies and describe the various improvements to EMBRs that have been made.

• Journal of Microbiology and Biotechnology
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• v.27 no.3
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• pp.573-583
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• 2017

Biofilm formation on the membrane surface results in the loss of permeability in membrane bioreactors (MBRs) for wastewater treatment. Studies have revealed that cellulose is not only produced by a number of bacterial species but also plays a key role during formation of their biofilm. Hence, in this study, cellulase was introduced to a MBR as a cellulose-induced biofilm control strategy. For practical application of cellulase to MBR, a cellulolytic (i.e., cellulase-producing) bacterium, Undibacterium sp. DM-1, was isolated from a lab-scale MBR for wastewater treatment. Prior to its application to MBR, it was confirmed that the cell-free supernatant of DM-1 was capable of inhibiting biofilm formation and of detaching the mature biofilm of activated sludge and cellulose-producing bacteria. This suggested that cellulase could be an effective anti-biofouling agent for MBRs used in wastewater treatment. Undibacterium sp. DM-1-entrapping beads (i.e., cellulolytic-beads) were applied to a continuous MBR to mitigate membrane biofouling 2.2-fold, compared with an MBR with vacant-beads as a control. Subsequent analysis of the cellulose content in the biofilm formed on the membrane surface revealed that this mitigation was associated with an approximately 30% reduction in cellulose by cellulolytic-beads in MBR.

• Membrane Journal
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• v.23 no.1
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• pp.24-44
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• 2013

The MBR technology has evolved rapidly over the past two decades with significant gains in performance and reliability, and reductions in costs. Membrane bioreactors (MBR) technology is widely recognised as offering a key option for enhanced wastewater treatment or reuse. The objective of this paper is then to critically review the remarkable achievement on the research and commercial applications of membrane bioreactor (MBR) technology and to present current and potential MBR markets on a global scope. This brief review of the technology incorporates five key aspects : 1) evolution of MBR practice, 2) the commercial technologies of MBRs, 3) the largest MBR installations globally (e.g. > $10,000m^3/day$), 4) MBR market growth, and 5) directions for future research. Finally, the development directions of economical, environmental and technical aspects in MBRs; 1) investment costs; 2) effluent water quality; 3) membrane materials and modules; 4) MBR equipment and treatment process; 5) operating costs (higher energy & chemical consumption); and 6) sustainability such as anaerobic MBRs in the coming years were addressed.

• Membrane and Water Treatment
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• v.6 no.6
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• pp.477-488
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• 2015

This study demonstrates that low pressure membranes are the ideal choice for industrial and/or municipal wastewater treatment by showing some promising experimental results, understanding different membrane filtration models, studying the potential of membrane bioreactors (MBRs), considering ceramic membranes fabrication and illustrating the role of nanotechnology in membranes. Cost study calculations are included to determine the treatment cost as well as the initial cost of various membrane types. Results showed that integrated membranes are preferred over MBR in case of average capacities. However, higher capacity situations are the most economical choice for MBR. It is shown that the least treatment cost in MBR was about $0.13/m^3$. However, the $0.13/m^3$ is the theoretical cost which is very small compared to the actual average MBR treatment cost of $0.5/m^3$.