Maize processing wastewater for electricity production in a microbial electrochemical cell

Abstract

Electrochemical cells have been fed organic matter in wastewater for depollution and energy production via microbial catalysis. Maize processing wastewater (MPWW) is rich in organics but is extremely alkaline, hindering the survival of microorganisms. The aim of the present work was to determine the feasibility of using MPWW to produce electricity in a bioelectrochemical cell. Raw MPWW was tested for electrochemically active microorganisms, thereafter a dilution strategy was implemented (1:2, 1:4, 1:10). A potential of +0.1 V was applied to the bioelectrochemical cell for 12 days and the current production was monitored as well as the decrease in chemical oxygen demand (COD). The raw MPWW contained electrochemically active microorganisms and the 1:2 dilution was the most favorable for current production reaching 100 mA m-2 in 9 days. The highest COD removal was 14%. This work demonstrates that MPWW can be exploited by industries for a cleaner production.