Membrane fouling reduction in a cost-effective integrated system of microbial fuel cell and membrane bioreactor.

Microbial fuel cells (MFC) and membrane bioreactors (MBR) are promising technologies for wastewater treatment. However, both of them have some drawbacks and application limitations. A cost-effective hybrid system (EMBR) integrating MFC with MBR was evaluated in terms of treatment performance and membrane fouling. In this paper, two electric field directions with a membrane module in the middle were applied to explore the mechanism of membrane fouling mitigation in EMBRs. In both configurations of EMBRs, microbial activity and degradation ability of activated sludge for chemical oxygen demand and NH4+-N removals could be enhanced compared with those for the controlled MBR. In addition, the irreversible resistance significantly decreased, especially in the EMBR(-) with a longer operation time. Furthermore, two critical factors, namely enhanced bioflocculation and electrophoresis forces, were compared based on key parameters (zeta potential, particle size distribution and extracellular polymeric substances). The electrophoresis forces made a greater contribution to fouling alleviation than that conducted by the enhanced bioflocculation. The results suggested that EMBR, as a promising wastewater treatment technology, improved effluent quality and reduced energy consumption.

Evaluation of energy-distribution of a hybrid microbial fuel cell-membrane bioreactor (MFC-MBR) for cost-effective wastewater treatment.

A low-cost hybrid system integrating a membrane-less microbial fuel cell (MFC) with an anoxic/oxic membrane bioreactor (MBR) was studied for fouling mitigation. The appended electric field in the MBR was supplied by the MFC with continuous flow. Supernatant from an anaerobic reactor with low dissolved oxygen was used as feed to the MFC in order to enhance its performance compared with that fed with synthetic wastewater. The voltage output of MFC maintained at 0.52±0.02V with 1000Ω resister. The electric field intensity could reach to 0.114Vcm(-1). Compared with the conventional MBR (CMBR), the contents rather than the components of foulants on the cake layer of fouled MFC-MBR system was significantly reduced. Although only 0.5% of the feed COD was translated into electricity and applied to MBR, the hybrid system showed great feasibility without additional consumption but extracting energy from waste water and significantly enhancing the membrane filterability.