Microbial Fuel Cell Operation and Use with Anaerobic Digestion for Power Production from Dairy Manure

摘要

At the start of the new millennium, it is important to find methods of energy generation and organic waste utilization that are sustainable for the future. Livestock manure has long been valued as a fertilizer and soil amendment, and more recently asa methane producer for heat and power via anaerobic digestion (AD). Microbial fuel cells (MFC) may offer an additional opportunity to gain value through direct electrical generation with little reduction in the manure's soil building value, while concurrently reducing the manure's pollution potential. We demonstrate that simple lab-scale MFCs capable of electrical production can be used with dairy manure and the microorganisms needed for are endogenously present. The system was operated with various rawmanure concentrations (0-100 g/L COD, 20 deg C), generating a maximum power density of 116 +- 23 mW/m~2 (COD 100 g/L). Power production was proportional to manure strength over the entire range. Anaerobic Digestion is adversely affected by temperaturereduction; however the MFCs still operate effectively. Average maximum power density increased with temperature from 8+-1 to 26+-5 mW/m~2, average total power from 0.56+-0.07 to 2.5+-0.35 J, while average COD destruction remained nearly the same (21 +-9%to 27+-10%). When used together, the operation of MFCs after AD was the better combination, with no reduction in MFC performance (12.9+-2.3 to 12.5+-2.2 C captured), while there appeared to be a tradeoff with MFC use before AD with an average biogas reduction of 20% (25+-2 to 20+-9mL).