Effect of electron acceptor on energy yield of wastewater microbial-based MFC

Abstract

This study evaluated the feasibility of using domestic and industrial wastewater as substrates for bioelectricity generation in microbial fuel cell (MFC) systems. Wastewater samples were collected from the Ulaanbaatar Central Wastewater Treatment Plant, and electrochemically active microorganisms were isolated and cultivated. Among 79 pure cultures, three isolates exhibited high electrochemical activity, as determined by cyclic voltammetry (CV). Domestic wastewater isolate DW29 exhibited the highest current (~2700 μA), followed by DW-1 (~2600 μ A) and industrial wastewater isolate IW-1 (~2200 μA). The effects of different cathodic electron acceptors on MFC performance were subsequently evaluated. Potassium permanganate (KMnO 4 ) produced the highest voltage output (~680–720 mV), followed by potassium dichromate (K 2 Cr 2 O 7 ), whereas potassium ferricyanide (K 3 Fe(CN) 6 ) exhibited the lowest performance. The combination of the industrial wastewater isolate IW-1 and KMnO 4 achieved the highest MFC performance, reaching a maximum voltage of approximately 765 mV and a power density of 66.11 mW/m³ in a two-chamber MFC system. These findings demonstrate that wastewater-derived electrochemically active microorganisms, together with an appropriate cathodic electron acceptor, can effectively enhance bioelectricity generation and have strong potential for sustainable wastewater treatment and renewable energy production.