Author(s): Zhang F, Ge Z, Grimaud J, Hurst J, He Z
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Abstract Two 4 L tubular microbial fuel cells (MFCs) were installed in a municipal wastewater treatment facility and operated for more than 400 days on primary effluents. Both MFCs removed 65-70\% chemical oxygen demand (COD) at a hydraulic retention time (HRT) of 11 h and reduced about 50\% suspended solids. The COD removal rates were about 0.4 (total) or 0.2 (soluble) kg m(-3) day(-1). They could handle fluctuation, such as emptying the anode for 1-3 days or different HRTs. The preliminary analysis of energy production and consumption indicated that the two MFCs could theoretically achieve a positive energy balance and energy consumption could be reduced using larger tubing connectors. Through linkage to a denitrifying MFC, the MFC system improved the removal of total nitrogen from 27.1 to 76.2\%; however, the energy production substantially decreased because of organic consumption in the denitrifying MFC. Establishing a carbon (electron) balance revealed that sulfate reduction was a major electron scavenger (37-64\%) and methane production played a very minor role (1.3-3.3\%) in electron distribution. These results demonstrate the technical viability of MFC technology outside the laboratory and its potential advantages in low energy consumption, low sludge production, and energy recovery from wastes.
This article was published in Environ Sci Technol
and referenced in Journal of Microbial & Biochemical Technology