The Performance Of Electricity Production And Organic Matter Degradation In River Sediment Microbial Fuel Cell

Sediment microbial fuel cell(SMFC) is a promising bioelechemical technology, which can achieve in-situ remediation and power output simultaneously. The characteristics of the sediment, the construction of SMFC and environmental factors all have significant effects on the capacity of power generation and organic matter degradation. River sediment of coastal city contains more organic matter and salt. The SMFC technology with the river sediment is often called River sediment microbial fuel cell(RSMFC). Combining the characteristics of River sediment of coastal city, the study aims to optimize power ourput and analyses organic matter degradation of RSMFC.Results from six kinds of sediments from different environment showed that RSMFC system could generate power spontaneously only under higher VS content(>12%) and SMFC systems with lower VS content could not generate electricity until periodically adding external carbon source. The highest power output was obtained by the high salinity sediment. Anaerobic sludge significantly inhibited power generation.Different from that of wastewater MFC, the external resistances had little effects on the RSMRC at the range of 20 ?-1000 ?. External resistances had effects on the RSMRC when it's higher than 2000 ?.Study of RSMFC with different electrode distance showed that the highest power density was abtained at the electrode distance of 4 cm. The power density decreased with electrode distance and the charge transfer was the major limitation of power output. Results alos showed that immersed cathode could also increase the power output from 22.1 mW/m2 to 39.1 mW/m2 and the Fe concentration in lake water can also improve the power output.Compared with the open circuit group, the readily oxidizable organic matter(ROOM) removal efficiency increased from 7.75% to 23.02% after 90 days of operation of RSMFC, which showed that RSMFC had powerful capacity of biological remedation. The ROOM removal efficiency is proportional to charge output.The current output increased from 0.1mA to 0.34 mA and maximum power density from 16.16 mW/m2 to 74.70 mW/m2 when the temperature of the reactors increased from 13-14 ? to 21-22 ?. The increase of temperature could also decrease the ohmic resistance.