Energy production from food industry wastewaters using bioelectrochemical cells

Abstract

Conversion of waste and renewable resources to energy using microbial fuel cells (MFCs) is an upcoming technology for enabling a cleaner and sustainable environment. This chapter assesses the energy production potential from the US food industry wastewater resource. It also reports on an experimental study investigating conversion of wastewater from a local milk dairy plant to electricity. An MFC anode biocatalyst enriched on model sugar and organic acid substrates was used as the inoculum for the dairy wastewater MFC. The tests were conducted using a two-chamber MFC with a porous three dimensional anode and a Pt/C air-cathode. Power densities up to 690 mW/m2 (54 W/m 3) were obtained. Analysis of the food industry wastewater resource indicated that MFCs can potentially recover 2-260 kWh/ton of food processed from wastewaters generated during food processing, depending on the biological oxygen demand and volume of water used in the process. A total of 1960 MW of power can potentially be produced from US milk industry wastewaters alone. Hydrogen is an alternate form of energy that can be produced using bioelectrochemical cells. Approximately 2-270 m3 of hydrogen can be generated per ton of the food processed. Application of MFCs for treatment of food processing wastewaters requires further investigations into electrode design, materials, liquid flow management, proton transfer, organic loading and scale-up to enable high power densities at the larger scale. Potential for water recycle also exists, but requires careful consideration of the microbiological safety and regulatory aspects and the economic feasibility of the process. © 2010 Springer Science+Business Media B.V.