Biomass Characteristics and Their Effect on Membrane Bioreactor Fouling

Abstract

Biomass characteristics are regarded as particularly influential for fouling in Membrane Bio-Reactors (MBRs). They primarily include the Mixed Liquor Suspended Solids (MLSS), the colloids and the Extracellular Polymeric Substances (EPS). Among them, the soluble part of EPS, which is also known as Soluble Microbial Products (SMP), is the most significant foulant, i.e., it is principally responsible for membrane fouling and affects all fundamental fouling indices, such as the Trans-Membrane Pressure (TMP) and the membrane resistance and permeability. Recent research in the field of MBRs, tends to consider the carbohydrate fraction of SMP (SMPc) the most important characteristic for fouling, mainly due to the hydrophilic and gelling properties, which are exhibited by polysaccharides and allow them to be easily attached on the membrane surface. Other wastewater and biomass characteristics, which affect indirectly membrane fouling, include temperature, viscosity, dissolved oxygen (DO), foaming, hydrophobicity and surface charge. The main methods employed for the characterization and assessment of biomass quality, in terms of filterability and fouling potential, can be divided into direct (such as FDT, SFI, TTF100, MFI, DFCM) or indirect (such as CST, TOC, PSA, RH) methods, and they are shortly presented in this review.

Energy-Efficient AnMBRs Technology for Treatment of Wastewaters: A Review

“…With regards to the membrane performance, it was generally accepted that temperature has a very significant impact on the permeate flux. Indeed, results obtained by Ozgun et al [157] clearly demonstrated that in terms of filtration performance, the AnMBR technology is not technically feasible for the treatment of municipal wastewater at 15 • C. The authors observed more severe fouling at 15 • C in comparison to 25 • C. Obviously, this is consistent with the fact that higher temperature results in decreased feed viscosity [168], higher mass transfer [169], reduced thickness of a cake layer [170] and finally, higher permeate flux.…”

New Insights into the Microbial Diversity of Cake Layer in Yttria Composite Ceramic Tubular Membrane in an Anaerobic Membrane Bioreactor (AnMBR)

“…Membrane fouling in AnCMBR is still a major bottleneck limiting its sustainable operation [13]. Generally, membrane fouling is the undesirable deposition of colloids, solutes, and accumulations of microorganisms and cell debris on membrane surfaces [14,15]. Cake layer formation on the membrane surface by organic and inorganic particles or biomaterial is the major contributor of the fouling in MBRs [16].…”

Fouling of membranes in membrane bioreactors for wastewater treatment: Planktonic bacteria can have a significant contribution

“…The isolation of soluble EPS is unfortunately not straightforward as many strategies exits and no standard method has been agreed upon (Rosenberger et al, 2005; Van den Broeck et al, 2011). Centrifugation is commonly used to remove the sludge flocs and various particles (Fan, Zhou, & Husain, 2006; Gkotsis & Zouboulis, 2019; Gkotsis, Zouboulis, & Mitrakas, 2020) whereas in other cases an additional filtration step (Van den Broeck et al, 2010) or heating step (Van De Staey et al, 2015) is included. Whether or not the planktonic bacterial cells are contained in the soluble EPS fraction can therefore vary.…”