Optimization of double chamber microbial fuel cell for domestic wastewater treatment and electricity production.

Abstract

Microbial fuel cells (MFCs) represent a new approach for treating waste water along with electricity production. The present study addressed electricity production from domestic wastewater using a mediator-less double chamber MFC. The electricity production was monitored under different operational conditions for both summer and winter samples. Optimization of the anodic and cathodic chambers resulted in a maximal current of 0.784 mA and 0.645 mA with the maximal power intensity of 209 and 117 mW/m2 in power duration of 24 h for the summer and winter samples, respectively. Scanning electron microscopy showed that the bacterial biofilm formation on the anode was denser for the summer sample than that when the winter sample was used, so was the total bacterial count. Therefore, samples taken during summer were considered better in electricity production and waste water treatment than those taken during winter basically because of the high microbial load during the hot season. In parallel, there was a decrease in both biological oxygen demand (BOD5) and chemical oxygen demand (COD) values which reached 71.8% and 72.85%, respectively at the end of the operation process for the summer sample, while there was no evident decrease for the winter sample. Optimizing the operating conditions not only increased the potential of using domestic waste water in microbial fuel cells to produce electricity, but also improved the quality of the domestic waste water.