Microbial fuel cells (MFCs) for bioelectrochemical treatment of different wastewater streams

Wastewaters generated from several industrial sources containing organic substrates present a vital basis for harnessing bioenergy. Aerobic wastewater treatment methods, for instance, activated sludge process and trickling filter are unsustainable due to constant energy requirements for aeration, and sludge management. Currently, Microbial Fuel Cell (MFC) technology presents an appropriate alternative for energy positive wastewater treatment and permits synchronized wastewater treatment, bioelectricity production, and resource recovery via bioelectrochemical remediation mediated by electroactive microbes. The added advantage of using MFC technology for effluent treatment is that several bio-based processes including removal of biochemical and chemical oxygen demand, nitrification, denitrification, sulfate removal and removal of heavy metals can be carried out in the same bioreactor. Thus, MFCs can both substitute and complement the conventional energy-intensive technologies for efficient removal as well as the recovery of sulfate, nitrogen, and phosphate without any tertiary treatment. Thus, the present review covers the recent advances in the utilization of microbial fuel cell technology for the removal of organic as well as recalcitrant pollutants from a wide range of industrial and domestic effluents with the simultaneous production of low-cost energy. Further this review discusses the hybrid systems developed in integration with conventional treatment systems to make the process energy neutral and thus pave a way to scale-up the MFCs for sustainable wastewater treatment. Moreover, some critical challenges related to the field applications of microbial fuel cell technology dealing with a wide range of effluents, have also been analyzed and presented.