Enhancing Electrogenesis by Pretreatment of Mixed Anaerobic Sludge To Be Used as Inoculum in Microbial Fuel Cells

Significant Coulombic loss in microbial fuel cells (MFCs) is attributed to utilization of the substrate and electrode space by nonexoelectrogenic micro-organisms. Selective enrichment of electrogens by inoculum pretreatment could offer solution to this problem. This study evaluates the effect of inoculum pretreatments such as acid treatment (pH levels of 4.0 and 5.3, via the addition of 0.1N H2SO4), heat, aeration, and ultrasonication on the performance of MFCs. Heat, ultrasonication, and acid pretreatments at pH of 5.3 were found to have an incremental effect on the power generation. MFC inoculated with acid-pretreated sludge at pH 5.3 produced a power density of 2.186 W m–3, which was ∼7 times greater than that produced by a control MFC inoculated with untreated sludge. MFC inoculated with aeration-pretreated sludge produced a slightly lower power density than control MFC. Acid pretreatment at pH of 4.0 was found unfavorable. Acid pretreatment at pH 5.3 was observed to be the most effective inoculum pretreatment, followed by ultrasonication and heat, for improving the Coulombic efficiency of MFCs.