Bioelectricity recovery and pollution reduction of distillery wastewater in air-cathode SCMFC

Abstract

Generation of electricity and treatment of the distillery wastewater (DW) were achieved in air-cathode single-chamber MFCs (SCMFCs). The maximum current density of 2.36 mA·m−2 and power density of 39.21 mW·m−3 were obtained at DW concentration of 2000 mg COD.L−1. The trends of current and power density were decreased with increasing concentration from 2000 to 4000 mg COD.L−1. The maximum soluble COD removal was 62.2% (CE = 8.77%, 1500 mg COD.L−1). The electrochemical activity of the microbes in the SCMFCs showed significantly high oxidized substrate in the semi-batch distillery wastewater operation. The microbial communities on the anode biofilms fed with a high concentration of distillery wastewater (4000 mg COD.L−1) operation were analyzed based on 454 pyrosequencing of the 16S rRNA gene revealed different microbial communities. The dominant phylum were Proteobacteria (28.5%), Bacteroidetes (23.4%) and Chlorobi (22.8%), while Firmicutes (9.3%) were detected as a lesser proportion of the total community. The microbial community structures suggested that Proteobacteria might be important for the production of power density in distillery wastewater fed air-cathode SCMFC. These results demonstrate that the SCMFCs can simultaneously generate electricity and achieve wastewater treatment from a renewable source.