Featured Research

from universities, journals, and other organizations

Fuel-cell Microbes' Double Duty: Treat Water, Make Energy

Date:
February 24, 2004
Source:
National Science Foundation
Summary:
Something big may be brewing on the sewage treatment circuit thanks to a new design that puts bacteria on double-duty-treating wastewater and generating electricity at the same time.

At their Pennsylvania State University lab, Bruce Logan watches as research colleague Hong Liu checks the circuit connections on the prototype microbial fuel cell. The jars behind it contain the "before" and "after" wastewater samples.
Credit: Greg Grieco, Penn State

ARLINGTON, Va.- Something big may be brewing on the sewage treatment circuit thanks to a new design that puts bacteria on double-duty-treating wastewater and generating electricity at the same time.

Related Articles


The key is an innovative, single-chambered microbial fuel cell. The prototype is described in the online version of the journal Environmental Science & Technology (http://pubs.acs.org/journals/esthag/); the article will also appear in a future print version of ES&T.

A fuel cell operates akin to a battery, generating electricity from a chemical reaction. But instead of running down unless it's recharged, the cell receives a constant supply of fuel from which electrons can be released. Typical fuel cells run off of hydrogen. In a microbial fuel cell, bacteria metabolize their food-in this case, organic matter in wastewater-to release electrons that yield a steady electrical current.

The single-chambered prototype, developed by researchers at Pennsylvania State University with support from the National Science Foundation (NSF), allows the process to work efficiently in wastewater.

In their paper, the researchers suggest that the improved design could usher in a "completely new approach" to wastewater treatment: "If power generation in these systems can be increased, microbial fuel cell technology may provide a new method to offset wastewater treatment plant operating costs, making advanced wastewater treatment more affordable for both developing and industrialized nations."

An $87,000 grant from NSF's Small Grants for Exploratory Research (SGER) program supported the project. Such SGER-called "sugar"-grants foster small-scale, innovative preliminary research on untested, novel ideas. They also sometimes fund quick- response research on natural disasters and other unanticipated events or support research to Scatalyze" emerging innovations.

The single-chambered microbial fuel cell is essentially a Plexiglass cylinder about the size of a soda bottle. Inside are eight graphite anodes (or negative electrodes), upon which the bacteria attach, and a hollow central cathode (or positive electrode). Electrons flow along a circuit wired from the anode to the cathode.

A steady flow of wastewater pumped into the chamber feeds the bacteria. Bacterial digestion of the wastewater's organic matter unleashes electrons into the electrical circuit and positively charged hydrogen ions into the solution. Those ions reduce the solution's oxygen demand, a key goal of wastewater treatment. The hydrogen ions also pass through a proton-exchange membrane to reach the cathode. Meanwhile, a hollow tube within the cylinder contains the cathode, which is exposed to air. At the cathode, oxygen from the air, hydrogen ions coming through the membrane and the electrons coming down the circuit combine to create water.

In other microbial fuel cells, microbes have been fed glucose, ethanol and other fuels, but, according to Bruce Logan, the Penn State professor of environmental engineering who leads the project, "Nobody has ever tried this with domestic wastewater. We're using something thought to be completely useless."

The single-chamber design is important, he said, because it facilitates a "continuous flow-through system," a design consistent with existing treatment systems.

By introducing air passively through the tube within the cathode layer, this model also greatly reduces the need for more aggressive - and energy-demanding - aeration schemes to treat the wastewater. Thus, as it creates electricity, it also reduces the need for it.

Each year in the United States, about 33 billion gallons of domestic wastewater is treated at cost of $25 billion; much of it pays for energy. If the microbial fuel cell can be applied on a larger scale, it could significantly reduce the energy costs of wastewater treatment.

It's not a small "if."

"We've got to make it cheaper," said Logan. "We can't afford to use graphite rods on the anodes, Nafion as the protonexchange membrane, and platinum on the carbon cathode. But we're already making progress on that. Substantially cheaper systems are just around the corner."

Meanwhile, amid the slime on the anodes, countless and various bacteria play distinctive roles in the breakdown of the wastewater and creation of electricity. "This is a whole community reaction," said Logan. "We're just beginning to appreciate and understand the complex bacterial community needed to generate electricity from wastewater."


Story Source:

The above story is based on materials provided by National Science Foundation. Note: Materials may be edited for content and length.


Cite This Page:

National Science Foundation. "Fuel-cell Microbes' Double Duty: Treat Water, Make Energy." ScienceDaily. ScienceDaily, 24 February 2004. <www.sciencedaily.com/releases/2004/02/040224081342.htm>.
National Science Foundation. (2004, February 24). Fuel-cell Microbes' Double Duty: Treat Water, Make Energy. ScienceDaily. Retrieved December 19, 2014 from www.sciencedaily.com/releases/2004/02/040224081342.htm
National Science Foundation. "Fuel-cell Microbes' Double Duty: Treat Water, Make Energy." ScienceDaily. www.sciencedaily.com/releases/2004/02/040224081342.htm (accessed December 19, 2014).

Share This


More From ScienceDaily



More Matter & Energy News

Friday, December 19, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Building Google Into Cars

Building Google Into Cars

Reuters - Business Video Online (Dec. 19, 2014) Google's next Android version could become the standard that'll power your vehicle's entertainment and navigation features, Reuters has learned. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
AP Review: Nikon D750 and GoPro Hero 4

AP Review: Nikon D750 and GoPro Hero 4

AP (Dec. 19, 2014) What to buy an experienced photographer or video shooter? There is some strong gear on the market from Nikon and GoPro. The AP's Ron Harris takes a closer look. (Dec. 19) Video provided by AP
Powered by NewsLook.com
Navy Unveils Robot Fish

Navy Unveils Robot Fish

Reuters - Light News Video Online (Dec. 18, 2014) The U.S. Navy unveils an underwater device that mimics the movement of a fish. Tara Cleary reports. Video provided by Reuters
Powered by NewsLook.com
3D Printed Cookies Just in Time for Christmas

3D Printed Cookies Just in Time for Christmas

Reuters - Innovations Video Online (Dec. 18, 2014) A tech company in Spain have combined technology with cuisine to develop the 'Foodini', a 3D printer designed to print the perfect cookie for Santa. Ben Gruber reports. Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins