A microbial fuel cell-electro-oxidation system for coking wastewater treatment and bioelectricity generation

BACKGROUND: Coking wastewater is generated from coal coking, coal gas purification, and by-product recovery processes. Increased interest is being focused on finding more sustainably effective and energy-efficient methods for treating this wastewater. In this work, a system termed microbial fuel cell-electro-oxidation (MFC-EO) was developed for simultaneous coking wastewater treatment and bioelectricity generation. RESULTS: Raw coking wastewater was first treated using MFCs. Power production, removal of total chemical oxygen demand (TCOD) and total nitrogen (TN) reached 538 +/- 9 mW m(-2), 52 +/- 1% and 50 +/- 1%, respectively. Wastewater strength and phosphate addition were evaluated for the enhancement of power production and treatment efficiency. At the EO stage, the effect of current density and chloride concentration on pollutant abatement, current efficiency (CEEO) and energy consumption (ECEO) were investigated. The overall removal of TCOD and TN was 82 +/- 1% and 68 +/- 1%, respectively using the MFC-EO process. CONCLUSIONS: A MFC-EO process was developed for the first time for simultaneous bioelectricity generation and coking wastewater treatment. This study attempted to combine MFCs with a conventional EO process for coking wastewater treatment. Further strategies need to be investigated to optimize reactor configuration using low-cost and highly efficient electrode materials. (C) 2009 Society of Chemical Industry