Introduction
Renewable energy (RE) applications are becoming a popular means of power generation within our society. Microbial fuel cells (MFCs) are a new form of renewable energy technology that can generate electricity from nearly any type of organic material found in marine sediments, sediments from rivers and lakes, or even wastewater. The Logan Research Group of Pennsylvania State University (PSU) describes MFC technology as a technology that uses bacterium already present in wastewater to generate electricity while simultaneously treating wastewater. Many researchers have proposed wastewater treatment as the primary application of MFCs in the future. Just recently, a team of researchers from the University of Queensland joined in partnership with the Foster’s Group to develop a pilot scale MFC that will run on Foster’s beer wastewater. It is true that MFCs produce less power than that of similar sized Proton Exchange Membrane (PEM) hydrogen fuel cells; however, please note that a combination of both electricity production and wastewater treatment would reduce the cost of treating primary effluent wastewater. The majority of the categories discussed in this blog will be on topics published by the mainstream media so all of the details discussed in this research blog is work that has already been performed and published (i.e. no “unpublished” work will be discussed so as to not expose any particular researcher’s new ideas). References will be appropriately given when required. Key words used in this field are designed as click-able links to Wikipedia web pages that will open up in a new web browser window.
Purpose
The purpose of this research blog is to generate feedback by professionals and non-professionals alike on MFC technology. The author of this blog would like to request a variety of commentary on this type of RE technology in hopes of progressing research, investigation, and eventually implementation of this technology.
January 22, 2007 at 5:26 pm
Hello Eric:
Curious whether you may have estimated the power that could be generated by a home septic tank (1500 gallons, family of 4)?
Jeff Lapides
January 29, 2007 at 3:43 am
Jeff,
Thank you for your comment. I believe an estimate could be made based on a few assumptions such as:
(1) 1 Watt per meter squared power density obtained from a MFC running on domestic water (anywhere from 0.5 to 1.5 Watts per meter squared are typical values recorded in scientific journals).
(2) 100-600 meter squared to meter cubed area/volume ratio of a typical trickling filter.
(3) A full 1500 gallon septic tank with a volume of 5.66 meters cubed.
Note: some of these assumptions are based on published works in the September 2006 issue of Environmental Science and Technology.
Simply multiplying these numbers together obtains 566 Watts to 3400 Watts of power. However, this calculation assumes the entire septic tank system as the anode portion and since the power density is in reference to the anode surface area and not the combination anode and cathode surface area, then perhaps the power output should quite a bit less then this calculated value. Another issue is the cost of the cathode material since it is catalyzed with platinum (Note: researchers are also looking into less expensive cobalt and iron based catalysts).
_Eric