ENVIRONMENTAL BIOTECHNOLOGY Electricity generation and treatment of paper recycling wastewater using a microbial fuel cell Liping Huang & Bruce E. Logan Received: 7 April 2008 / Revised: 13 May 2008 / Accepted: 14 May 2008 / Published online: 10 June 2008 # Springer-Verlag 2008 Abstract Increased interest in sustainable agriculture and bio-based industries requires that we find more energy- efficient methods for treating cellulose-containing waste- waters. 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/m 2 , 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/m 2 . In contrast, only 144±7 mW/m 2 was produced using an unamended waste- water (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. Keywords Microbial fuel cell . Paper recycling wastewater . Cellulose . Solution conductivity . Power production Introduction With the continued increased consumption of paper products and other natural fiber products, the recycling and use of recovered paper is growing worldwide. The average amount of recycling content in paper production was increased by 22% from 1990 to 1998. In 2005, 78% of paper and paperboard mills in America used some recovered paper, and 149 mills used only recovered paper. By 2012, it is projected that the paper industry will recover 55% of all the paper Americans consume (Lens et al. 2002). The strength of wastewater in a paper recycling plant generally increases with the percent of recycled content. Thus, an increase in the relative proportion of recovered paper and an increase in the amount of paper produced will lead to increased energy demands for wastewater treatment using conventional treatment processes. In addition, this wastewater contains soluble organics and particulate matter such as cellulose which are not effectively degraded by traditional wastewater treatment technologies (Lens et al. 2002). Many paper recycling industries therefore have an interest in reducing water use, finding more effective methods to treat their wastewater as well as decreasing costs for wastewater treatment. One new promising method for wastewater treatment is the use of microbial fuel cells (MFCs). Bacteria in an MFC grow under anoxic conditions, which can benefit cellulose fermentation and degradation, with the added benefits of electricity generation rather than power consumption (Huang et al. 2008; Logan and Regan 2006). Several types of wastewaters have been successfully treated with simul- Appl Microbiol Biotechnol (2008) 80:349–355 DOI 10.1007/s00253-008-1546-7 L. Huang School of Environmental and Biological Science and Technology, Dalian University of Technology, Dalian 116024, China L. Huang : B. E. Logan (*) Department of Civil and Environmental Engineering, The Pennsylvania State University, University Park, PA 16802, USA e-mail: blogan@psu.edu