Submersible microbial fuel cell for electricity production from sewage sludge

Abstract

A submersible microbial fuel cell (SMFC) was utilized to treat sewage sludge and simultaneously generate electricity. Stable power generation (145 ± 5 mW/m², 470 Ω) was produced continuously from raw sewage sludge for 5.5 days. The maximum power density reached 190 ± 5 mW/m². The corresponding total chemical oxygen demand (TCOD) removal efficiency was 78.1 ± 0.2% with initial TCOD of 49.7 g/L. The power generation of SMFC was depended on the sludge concentration, while dilution of the raw sludge resulted in higher power density. The maximum power density was saturated at sludge concentration of 17 g-TCOD/L, where 290 mW/m² was achieved. When effluents from an anaerobic digester that was fed with raw sludge were used as substrate in the SMFC, a maximum power density of 318 mW/m², and a final TCOD removal of 71.9 ± 0.2% were achieved. These results have practical implications for development of an effective system to treat sewage sludge and simultaneously recover energy.

Key findings

• ▸Stable power generation of 145 ± 5 mW/m² was produced continuously for 5.5 days
• ▸Maximum power density reached 190 ± 5 mW/m² with 78.1% total chemical oxygen demand removal efficiency
• ▸Power generation depended on sludge concentration, with higher power density achieved through dilution of raw sludge

Keywords

Identifiers

DOI

10.2166/wst.2011.678

Journal

Water Science and Technology

Year

2011