Impact of Anodic Respiration on Biopolymer Production and Consequent Membrane Fouling

Abstract

Microbial fuel cells (MFCs) have recently been integrated with membrane bioreactors (MBRs) for wastewater treatment and energy recovery. However, the impact of integration of the two reactors on membrane fouling of MBR has not been reported yet. In this study, MFCs equipped with different external resistances (1-10 000 ohm) were operated, and membrane-fouling potentials of the MFC anode effluents were directly measured to study the impact of anodic respiration by exoelectrogens on membrane fouling. It was found that although the COD removal efficiency was comparable, the fouling potential was significantly reduced due to less production of biopolymer (a major foulant) in MFCs equipped with lower external resistance (i.e., with higher current generation) as compared with aerobic respiration. Furthermore, it was confirmed that Geobacter sulfurreducens strain PCA, a dominant exoelectrogen in anode biofilms of MFCs in this study, produced less biopolymer under anodic respiration condition than fumarate (anaerobic) respiration condition, resulting in lower membrane-fouling potential. Taken together, anodic respiration can mitigate membrane fouling of MBR due to lower biopolymer production, suggesting that development of an electrode-assisted MBR (e-MBR) without aeration is feasible.

Membrane fouling induced by AHL-mediated soluble microbial product (SMP) formation by fouling-causing bacteria co-cultured with fouling-enhancing bacteria

“…In addition, possible combinations of QQ and other approaches such as chlorination 47 , enrichment of fouling-reducing bacteria (i.e. Bacillus and Chloroflexi ) 48 , 49 , and anodic respiration 24 should be investigated for efficient membrane fouling mitigation.…”

“…Carbohydrate and protein concentrations in dialyzed SMP were quantified with phenol-sulfonic acid method using glucose as the standard and Lowry method using BSA as the standard, respectively. In order to estimate the quantities of SMP trapped on membrane, carbohydrate and protein in SMP before and after the dead-end filtration was measured 24 .…”

A spontaneous electric field membrane bioreactor with the innovative Cu‐nanowires conductive microfiltration membrane for membrane fouling mitigation and pollutant removal

“…The microbe density on the cultured membrane surfaces was determined by the lipid phosphorus method (Aelterman, Freguia, Keller, Verstraete, & Rabaey, ). Extracellular polymeric substances (EPS), divided into loosely bound EPS (LB‐EPS) and tightly bound EPS (TB‐EPS), and soluble microbial products (SMP), were extracted and determined by the reported methods (Ishizaki et al., ; Liu et al., ). The effluents of the anaerobic and aerobic tanks were filtered through a 0.45‐μm filter (cellulose acetate membrane‐11306, 20 mm in diameter, Sartorius Co., Ltd, Germany).…”

“…With the rapid progress in the development of membrane bioreactors (MBRs) technology, membrane has been applied for the purpose to reuse the effluent worldwide. However, membrane fouling is inevitable during long‐term operation and substantially obstructs treatment efficiency (Ishizaki, Terada, Miyake, & Okabe, ). Recent efforts have been mostly focused on improving membrane fouling mitigation, such as superfluous aeration, modification of membranes, improvement of operation performance, and so on.…”

Membrane Fouling Potentials of an Exoelectrogenic Fouling-Causing Bacterium Cultured With Different External Electron Acceptors

“…It has been recently reported that membrane fouling was mitigated by integrating MFC and MBR due to less production of soluble microbial products (SMP) and extracellular polymeric substances (EPS) under anodic respiration conditions (Su et al, 2013; Tian et al, 2014; Ma et al, 2015). In particular, the production of biopolymer, which is well known as a main foulant, was significantly reduced in mixed population biomass in electrode-associated MBR (e-MBR) (Tian et al, 2013, 2014; Ishizaki et al, 2016b). Furthermore, a pure culture of Geobacter sulfurreducens strain principle compartment analysis (PCA), an exoelectrogenic bacterium, produced less biopolymer and consequently exhibited lower membrane fouling under anodic respiration condition than under fumarate (anaerobic) respiration condition (Ishizaki et al, 2016b).…”