Grantee Research Project Results
Final Report: Microbial Desalination Fuel Cell as a Sustainable Technology for Renewable Water and Power
EPA Grant Number: SU836030Title: Microbial Desalination Fuel Cell as a Sustainable Technology for Renewable Water and Power
Investigators: Jiang, Sunny C. , Gellers, Joshua C. , Jeung, Matthew K. , Glenn, Errol M. , Tseng, Linda Y. , Lim, Keah Ying , Karmen, Andrew , Y.Orellana, Dean , Katebian, Leda , Jiang, Luman , Huang, Siqian , Tu, Tiffany , Huang, Xiao , Wu, Yanwen
Institution: University of California - Irvine
EPA Project Officer: Hahn, Intaek
Phase: I
Project Period: August 15, 2011 through August 14, 2012
Project Amount: $15,000
RFA: P3 Awards: A National Student Design Competition for Sustainability Focusing on People, Prosperity and the Planet (2011) RFA Text | Recipients Lists
Research Category: Pollution Prevention/Sustainable Development , P3 Challenge Area - Air Quality , P3 Challenge Area - Safe and Sustainable Water Resources , P3 Awards , Sustainable and Healthy Communities
Objective:
The proposal objective is to design a microbial desalination fuel cell (MDFC) as a pretreatment to the current seawater desalination plant that will provide sustainable freshwater supply for human consumption at minimal energy cost. This objective will be achieved through the MDFC’s innovative abilities to desalinate seawater and generate energy to sustain the long-term prosperity of people and environment.
The MDFC combines the recent development of Microbial Fuel Cell (MFC) research with the traditional electrodialysis to remove salts from seawater while generate electrical energy at the expenses of microbial metabolic activity and organic wastes. This technology reduces the cost of seawater desalination for drinking water production, reduces pollution and waste emissions, and serves as an educational model to the public on the innovative technology to sustain people and environment.
Summary/Accomplishments (Outputs/Outcomes):
To optimize power production and reduce the cost for scale-up MDFC, a membrane-less MFC with an aerobic biocathode was first designed. The MFC generated a stable voltage between 500 and 550 mV and removed 82% chemical oxygen demand (COD) from the influent, with 27% attributed to the anoxic process in the anode and 55% to the aerobic process in the cathode. In comparison with the traditional wastewater treatment for COD removal, MFC treatment of organicd is equivalent to a 33% reduction in aeration energy requirement. Currently the MFC can generate power density of 0.55 mW based on an anode volume of 700 mL using an external resistor load (Ω = 100 ohms). Assuming a linear scale-up of the system, these results would correspond to a power generation of 0.79 W/m3 anode chamber volume or 0.092 W/m2 anode surface area.
To evaluate the sustainability of MFC for organic substrates removal, a carbon foot print (CFP) analysis was performed and compared to that of the activated sludge process (ASP) in traditional wastewater treatment. The analysis showed that one of the key advantages of MFC is a significant reduction of oxygen requirement for degradation of COD. Because the influent COD is first removed in the anoxic anode chamber before consumption by microbes in the aerobic chamber. In comparison, ASP consumes 40-70% of the total energy in municipal wastewater treatment due to high demands of oxygen diffusion. The MFC design would result in reduced blower power consumption from 1.5 kWh/kg-COD removed by ASP to 1.0 kWh/kg-COD removed based on the data from our laboratory-scale MFC. In addition, the low bio-sludge yield (measured by volatile suspended solids, or VSS) was observed in the anaerobic process in the MFC. This is due to the inherent nature of the anaerobic process where most of the energy generated by the anaerobes is used for cell maintenance instead of cell growth. This reduction in total bio-sludge equates to additional energy savings attributed by the reduced volume of waste disposal. In large urban areas, long-distance transport of sludge waste for disposal constitutes one of the important energy requirements for conventional ASP.
To educate the public on the innovative technology to sustain people and environment, the outreach portion of our project involved creating K-12 lesson plans and planning classroom demonstrations, website development, social science literature review, and a seminar series. Our website contained updated information on all facets of the project: sustainable engineering and research, MDFC practicality, modeling, and education and outreach activities. To understand and address some of the potential concerns about the proposed MDFC-SWRO system, we met with experts from various fields and scheduled speakers to participate in the seminar series in April.
Conclusions:
The team verified that a membrane-less MFC that uses biocathode was able to replace expensive catalysts and catholytes. The energy generation was comparable to the previous published literature. According to our carbon footprint model using wastewater as the nutrient input, the MDFC can achieve 14% reduction of energy consumption comparing to a conventional wastewater activated sludge process. The team’s contact network now consists of a group of experts in energy and desalination, local environmental groups, and local K-12 school teachers. The feedback from experts in energy and desalination and local environmental groups were used to improve the MDFC project. The team identified potential concerns in the pilot implementation of MDFC.
Supplemental Keywords:
Life cycle analysis, cost benefit assessment, seawater reverse osmosis (SWRO), membrane treatment technology, environmental education, decision-making, alternative energy source, renewable energy, renewable fuel, fuel cells, water purification technology, drinking water treatment technologiesThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.