Direct recovery of electrical energy from municipal wastewater by microbial fuel cells with Low voltage booster rectifier (LVBR)

Abstract

 Microbial fuel cells (MFCs) can simultaneously treat wastewater and recover renewable energy, but their output voltage and power are low. Therefore, a voltage booster rectifier (LVBR) consisting of a DC/AC voltage booster (LVB) and a rectifier and charger was developed to boost low MFC output voltage to usable levels. In the present study, the electric energy recovery rate from wastewater was evaluated for the following two connection methods of the MFC and LVBR. Three Each individual air-cathode MFC was connected to an LVB (MFC-LVB units), and then three MFC-LVR units were parallelly connected to a rectifier/charger (MFC-LVBR I).Three air-cathode MFCs were parallelly connected to an LVB and then connected to a rectifier/charger (MFC-LVBR II).Asupercapacitor (16.2 V, 83.3 F) was charged for 72 h, and the voltage was increased to 2.68 Vwith a charging efficiency of 31.2 % for MFC-LVBR I and to 3.10 V with a charging efficiency of 35.9 % for MFC-LVBR II, respectively.