Single-chamber bioelectrochemical hydrogen fermentation from garbage slurry

Abstract

Bioelectrochemical systems (BESs) can control electric flow and resultant microbial activity. We designed a single chamber BES to investigate hydrogen production from artificial garbage slurry. A 3-electrode system was applied and the potential of the working electrode was regulated to −1.0V (vs. Ag/AgCl). Thus, the potential on the counter electrode was 1.38V (vs. Ag/AgCl). Hydrogen fermentation in the BES was initiated by methanogenic seed sludge. The BES achieved a hydrogen production rate of 2196mLL−1day−1 at an organic loading rate of 58.7g dichromate chemical oxygen demandL−1day−1. Acetate and butyrate were the main products, indicating that favorable hydrogen fermentation occurred in the system. Combination of high potential on the counter electrode and relatively low pH condition (5.5–6.4) was effective for constructing hydrogen fermentation even in single chamber system by inhibiting methanogenesis. However, it may be necessary to increase the space between the working and counter electrodes so as to decrease the electrical input. The single-chamber BES could be scaled-up for efficient hydrogen fermentation from garbage slurry.