text-only page produced automatically by LIFT Text Transcoder Skip all navigation and go to page contentSkip top navigation and go to directorate navigationSkip top navigation and go to page navigation
National Science Foundation
News
design element
News
News From the Field
For the News Media
Special Reports
Research Overviews
NSF-Wide Investments
Speeches & Lectures
NSF Current Newsletter
Multimedia Gallery
News Archive
News by Research Area
Arctic & Antarctic
Astronomy & Space
Biology
Chemistry & Materials
Computing
Earth & Environment
Education
Engineering
Mathematics
Nanoscience
People & Society
Physics
 

Email this pagePrint this page

Press Release 04-021 - Video
Fuel-Cell Microbes' Double Duty: Treat Water, Make Energy

Scene from animation schematically showing the anatomy of the single-chambered microbial fuel cell.
View Video

This National Science Foundation animation schematically shows the anatomy of the single-chambered microbial fuel cell developed at Pennsylvania State University.

Credit: Trent L. Schindler / National Science Foundation

Back to article

Video Transcript:


Down the center of the microbial fuel cellís single chamber runs the cathode, or positive electrode. It consists of a perforated plastic tube, which allows air to enter the fuel cell. Covering the tube is a layer of Nafion, a membrane through which protons may pass. A wire comes off the cathode to allow the circuit to be connected.

Eight graphite rods combine to serve as the anode, or negative electrode of the cell.

The anode and cathode are housed in a chamber into which wastewater flows.

Bacteria in the wastewater attach themselves to the anode rods and, by the chemistry of their metabolism, break down the organic matter in the wastewater. This releases electrons to the anodes and hydrogen protons into the solution. The protons (positive hydrogen ions) then pass through the proton exchange membrane of the cathode. At the cathode, oxygen from the air, the hydrogen ions coming through the membrane and the electrons coming down the circuit from the anode combine to create water.

Connecting the positive and negative electrodes, and placing an electrical load between them, would complete an electrical circuit. Meanwhile, the bacteria also remove up to 78 percent of organic matter as measured by biochemical oxygen demand, a key factor in the treatment of wastewater. (As the wastewater flows in, the treated effluent departs the chamber from a tube not shown.)



Related media icon
This video requires the free RealPlayer plug-in

 



Email this pagePrint this page
Back to Top of page