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Final Report: Electricity Generation From Anaerobic Wastewater Treatment in Microbial Fuel Cells (MFCs)EPA Contract Number: EPD09022
Title: Electricity Generation From Anaerobic Wastewater Treatment in Microbial Fuel Cells (MFCs)
Investigators: Curtis, Michael D.
Small Business: Fuss & O’Neill
EPA Contact: Manager, SBIR Program
Project Period: February 1, 2009 through August 31, 2009
Project Amount: $70,000
RFA: Small Business Innovation Research (SBIR) - Phase I (2009) RFA Text | Recipients Lists
Research Category: Small Business Innovation Research (SBIR) , SBIR - Water and Wastewater
The purpose of the research conducted in this SBIR project was to initiate the development of anaerobic microbial fuel cell (MFC) technology for commercial use. Microbial fuel cells are a promising technology for sustainable wastewater treatment. Wastewater treatment is critical for protecting the environment. Wastewater treatment processes, however, consume large amounts of energy, an estimated 2 percent of energy consumed nationwide. MFCs utilize the bacteria commonly used in biological wastewater treatment processes to harvest the chemical energy stored in contaminants and convert it to electricity.
In laboratory-scale research, MFCs have been well proven to simultaneously treat organic wastewater and generate electricity. Most MFC studies, however, have been limited to small (typically < 250 mL) batch reactors using laboratory-created simulated wastewater. To make this important technology available for future full-scale use, it must be demonstrated to be effective in larger continuous-flow systems. Using MFCs to treat municipal wastewater as the substrate would provide an enormous market for commercialization. This project was the first pilot-scale project to demonstrate that municipal wastewater could be effectively treated and generate electricity using MFCs.
The research described below was performed using funds from the SBIR Program along with two other generous grants from groups committed to helping to commercialize MFCs. Four multi-anode/cathode granular activated carbon MFCs (MAC-GACMFC) with a working volume of 16 L and 12 circuits each were designed, constructed, and operated at the Gloversville-Johnstown Joint Wastewater Treatment Facility in Johnstown, NY, during 2009. Initially, two reactors were completed, one in an upflow mode and one in a downflow mode. The upflow mode was determined to be the preferred configuration, so the third and fourth reactors were constructed in an upflow mode. During this time, several other improvements were made to the design, based on experience during start-up.
The first two reactors were acclimated in May through July 2009, first using sodium acetate (NaAc) and then a mixture of primary effluent supplemented with NaAc to develop a healthy biofilm on the granular activated carbon (GAC) media. Then, the first two reactors were operated using solely municipal primary effluent as the substrate. After primary effluent became the sole substrate, these reactors were operated at a hydraulic retention time of 20 hours, at a temperature of approximately 30°C, with 100 ohm external resistance. Acclimation of the third and fourth reactors began in mid-August 2009. Municipal primary effluent also will be used as the sole substrate in these reactors after they are acclimated.
This study provided extensive valuable information about the use of MFCs for municipal wastewater treatment.
- The results of this study were very promising, showing that, under the test conditions, the wastewater can be very effectively treated. Treated effluent had chemical oxygen demand (COD) concentrations of less than 30 mg/L, meeting EPA secondary treatment standards for organics. This very positive result was surprising because typically, anaerobic processes do not achieve this level of COD removal.
- During the entire study, the reactors also successfully generated electricity. Because the amount of electricity generated was below the maximum rates that have been seen in the laboratory scale, new concepts of how to improve electrical efficiency currently are being developed by the project team for future testing.
- The first and second generations of MAC-GACMFC systems developed in the Phase I project demonstrated that the improvement of MFC configurations and materials substantially enhanced power generation and wastewater treatment efficiency. Electricity generation is fairly efficient, but subject to enhancement by reducing internal resistance and by maintaining the cathode surfaces.
- There is a tendency for the cathode surfaces to foul over time. This results in degradation of electrical efficiencies (with no change in COD removal). It was found that when the cathodes are cleaned, there is an immediate improvement in electrical efficiency.
- Power additivity has been demonstrated with the multiple anode/cathode pairs. Thus, 12 circuits produce significantly more power than a single circuit of the same size.
This groundbreaking study, the first ever pilot-scale study using MFCs to treat municipal wastewater, was successful. This study demonstrated that highly effective wastewater treatment can be achieved simultaneously with power generation. MFCs' effectiveness in treating municipal wastewater presents nearly boundless opportunities for commercial use of this technology. Continued development should address the following issues:
- Evaluate the use of MFCs under a broader range of operating conditions (lower HRT, temperature, etc.);
Optimize the technology for increased power output;
Continue research to determine operation and maintenance requirements; and
Modify reactor design to improve access for maintenance.
CommercializationThe success of the pilot-scale MFCs opens a huge new market in municipal wastewater treatment for this technology. Previously, there was some thought that perhaps industrial wastewater might provide MFCs' only market niche. As a first formal step toward commercialization, Foresight Technologies was hired to perform a Technology Niche Analysis (TNA) for MFCs. The TNA confirmed the team’s initial expectations that this technology would best be developed in partnership with a small wastewater treatment company. With this in mind, the project team has begun to develop a relationship with a small wastewater treatment products company that is detailed further in the SBIR Phase II application.
Journal Articles on this Report : 2 Displayed | Download in RIS Format
|Other project views:||All 2 publications||2 publications in selected types||All 2 journal articles|
||Jiang D, Li B. Granular activated carbon single-chamber microbial fuel cells (GAC-SCMFCs): a design suitable for large-scale wastewater treatment processes. Biochemical Engineering Journal 2009;47(1-3):31-37.||
||Li X, Hu B, Suib S, Lei Y, Li B. Manganese dioxide as a new cathode catalyst in microbial fuel cells. Journal of Power Sources 2010;195(9):2586-2591.||