Effect of Activated Sludge Properties and Membrane Operation Conditions on Fouling Characteristics in Membrane Bioreactors


Biofouling control is considered to be a major challenge in operating membrane bioreactors (MBRs) for the treatment of wastewater. This study examined the impact of biological, chemical, and physical properties of activated sludge on membrane filtration performance in laboratory-scale MBRs. Sludges with different microbial communities were produced using pseudo-continuous stirred-tank reactors and pseudo-plug flow reactors treating a synthetic paper mill wastewater. Various filtration resistances were used to investigate membrane fouling characteristics, and molecular biology tools targeting 16S ribosomal DNA gene sequences were used to identify predominant bacterial populations in the sludges or attached to the fouled membranes. Filtration experiments using axenic cultures of Escherichia coli, Acinetobacter calcoaceticus, and Gordonia amarae were also performed to better understand the initiation and development of biofouling. The results showed that the tendency of membranes to biofoul depended upon membrane operating conditions as well as the properties of the activated sludge in the MBR systems. Specific bacterial populations, which were not dominant in the activated sludges, were selectively accumulated on the membrane surface leading to the development of irreversible biofouling.


Civil, Architectural and Environmental Engineering

Keywords and Phrases

DNA; Escherichia coli; Filtration; Fouling; Gene transfer; Sewage sludge; Wastewater treatment; Bacterial populations; Continuous stirred-tank reactors; Filtration resistances; Membrane bioreactors; Paper mill wastewater; Plug flow reactors; Bioreactors; ribosome DNA; DNA; activated sludge; biofouling; bioreactor; gene; microbial community; pulp and paper industry; waste treatment; Acinetobacter calcoaceticus; bacterium culture; gene sequence; Gordonia amarae; laboratory; membrane filter; microflora; paper industry; waste water management; Bacteria; Bacterial; Sewage; Waste Disposal; Fluid; Bacteria (microorganisms); Continuous stirred-tank reactor; Filtration resistance; Molecular biology; Plug flow reactor

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Article - Journal

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© 2006 Elsevier Limited, All rights reserved.

Publication Date

01 Jun 2006