Increased interest in sustainable agriculture and bio-based industries requires that we find more energy-efficient methods for treating cellulose-containing wastewaters. We examined the effectiveness of simultaneous electricity production and treatment of a paper recycling plant wastewater using microbial fuel cells. Treatment efficiency was limited by wastewater conductivity. When a 50 mM phosphate buffer solution (PBS, 5.9 mS/cm) was added to the wastewater, power densities reached 501±20 mW/m2, with a coulombic efficiency of 16±2%. There was efficient removal of soluble organic matter, with 73±1% removed based on soluble chemical oxygen demand (SCOD) and only slightly greater total removal (76±4%) based on total COD (TCOD) over a 500-h batch cycle. Cellulose was nearly completely removed (96±1%) during treatment. Further increasing the conductivity (100 mM PBS) increased power to 672±27 mW/m2. In contrast, only 144±7 mW/m2 was produced using an unamended wastewater (0.8 mS/cm) with TCOD, SCOD, and cellulose removals of 29±1%, 51±2%, and 16±1% (350-h batch cycle). These results demonstrate limitations to treatment efficiencies with actual wastewaters caused by solution conductivity compared to laboratory experiments under more optimal conditions.
All Science Journal Classification (ASJC) codes
- Applied Microbiology and Biotechnology