Microbial Fuel Cell (MFC): An Innovative Technology for Wastewater Treatment and Power Generation

Abstract

Microbial fuel cells (MFCs) have been nominated as new alternatives and novel opportunities which are able to convert biodegradable organic matters (as substrates) into green electricity with the aim of different types of active microorganisms as active biocatalysts. In terms of configurations, one-chambered MFCs (OC-MFCs), dual-chambered MFCs (DC-MFCs), tubular, H-type, upflow MFCs, and stacked ones would be introduced each for specific objectives. Basically, MFC configuration consists of a biological anode and an abiotic cathode chamber separated by a proton exchange membrane. Direct production of electricity out of substrates, enabling to be operated efficiently at an ambient temperature, and expanding the diversity of fuels used as energy requirements are some of the most praiseworthy advantages of MFCs. Due to electron and proton release resulted by oxidized substrates in anode compartment, sufficient information about electron transfer mechanisms of microorganisms is essential to reach raising amount of energy produced by an MFC system and to find out the theory about their operation. In the 1980s, scientists have figured out that adding some electron mediators causes an incredible enhancement in power output and current density of mentioned technology. By this demonstration, the mediator acts as a movable agent which transports electrons between electrode and bacteria in anode part. Moreover, the most useful applications of MFCs can be classified into four significant categories. They have the ability to be used for electricity production, generation of biological hydrogen, and wastewater treatment (WWT) plants. Besides, MFCs was used as power generator for sensors and biosensors or serve as biosensors themselves. Hence, use of MFCs in water quality improvement which is related to WWT has attracted many scientists all over the world over recent years. Consequently, by using these novel technologies, online monitoring of various parameters related to water quality such as biological oxygen demand, toxicity, and total organic carbon is achievable.