Long-term performance of a 20-L continuous flow microbial fuel cell for treatment of brewery wastewater Mengqian Lu a, b , Shing Chen a, b , Sofia Babanova a, b , Sujal Phadke a, b , Michael Salvacion a, b, c , Auvid Mirhosseini a, d , Shirley Chan a, b , Kayla Carpenter a, e , Rachel Cortese a, b , Orianna Bretschger a, b, * a Department of Microbial and Environmental Genomics, J. Craig Venter Institute, 4120 Capricorn Lane, La Jolla, CA 92037, USA b Aquam LLC, 4683 Mercury St. Suite C, San Diego, CA, 92111, USA c Spark Aerial Inc., 448 Market St. Suite 201, San Diego, CA, 92101, USA d Geosyntec Consultants, 900 Broken Sound Pkwy NW, Suite 200, Boca Raton, FL, 33487, USA e Columbia University Medical Center, 701 W 168 Street, New York, NY,10032, USA highlights  A 20 L MFC system containing two 10 MFC reactors was constructed.  No catalysts, Nafion or ion exchange membrane was used.  The MFC system was operated with brewery wastewater for nearly a year.  Operational conditions were tested and the MFCs can recover from equipment failure.  The highest COD removal efficiency is 94.6 ± 1.0%. article info Article history: Received 8 January 2017 Received in revised form 26 March 2017 Accepted 27 March 2017 Available online 7 April 2017 Keywords: Microbial fuel cell Scaling-up Long-term performance Brewery wastewater treatment abstract Microbial fuel cells (MFCs) have been shown as a promising technology for wastewater treatment. Integration of MFCs into current wastewater treatment plant have potential to reduce the operational cost and improve the treatment performance, and scaling up MFCs will be essential. However, only a few studies have reported successful scale up attempts. Fabrication cost, treatment performance and oper- ational lifetime are critical factors to optimize before commercialization of MFCs. To test these factors, we constructed a 20 L MFC system containing two 10 L MFC reactors and operated the system with brewery wastewater for nearly one year. Several operational conditions were tested, including different flowrates, applied external resistors, and poised anodic potentials. The condition resulting in the highest chemical oxygen demand (COD) removal efficiency (94.6 ± 1.0%) was a flow rate of 1 mL min 1 (HRT ¼ 313 h) and an applied resistor of 10 U across each MFC circuit. Results from each of the eight stages of operation (325 days total) indicate that MFCs can sustain treatment rates over a long-term period and are robust enough to sustain performance even after system perturbations. possible ways to improve MFC performance were discussed for future studies. © 2017 Elsevier B.V. All rights reserved. 1. Introduction Wastewater treatment is an energy extensive process. Each year, wastewater treatment consumed approximately 110 TWh, which is about 3e4% of the United States' electrical energy load. In the United States, each year $25 billion is spent on domestic waste- water treatment, and another $300 billion is spent on wastewater treatment plants. Based on the wastewater type and the process, wastewater treatment may require energy of 0.5e2 kWh m 3 of wastewater. By now, the well-established activated sludge (aerobic digestion) process has been used in most wastewater treatment systems. Although highly efficient and fast, this process is chemi- cal- and energy-intensive with high capital and significant * Corresponding author. Aquam LLC, 4683 Mercury St. Suite C, San Diego, CA, 92111, USA. E-mail address: orianna.bretschger@aquam.tech (O. Bretschger). Contents lists available at ScienceDirect Journal of Power Sources journal homepage: www.elsevier.com/locate/jpowsour http://dx.doi.org/10.1016/j.jpowsour.2017.03.132 0378-7753/© 2017 Elsevier B.V. All rights reserved. Journal of Power Sources 356 (2017) 274e287