Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Fuel-cell microbes’ double duty: treat water, make energy

24.02.2004


NSF ’sugar’ grant supports single-chamber prototype fed by wastewater


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



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.

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."

Sean Kearns | NSF
Further information:
http://pubs.acs.org/journals/esthag
http://www.nsf.gov
http://www.psu.edu/ur/2004/microbfuel.html

More articles from Power and Electrical Engineering:

nachricht Open, flexible assembly platform for optical systems
24.01.2017 | Fraunhofer-Institut für Produktionstechnologie IPT

nachricht A big nano boost for solar cells
18.01.2017 | Kyoto University and Osaka Gas effort doubles current efficiencies

All articles from Power and Electrical Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Scientists spin artificial silk from whey protein

X-ray study throws light on key process for production

A Swedish-German team of researchers has cleared up a key process for the artificial production of silk. With the help of the intense X-rays from DESY's...

Im Focus: Quantum optical sensor for the first time tested in space – with a laser system from Berlin

For the first time ever, a cloud of ultra-cold atoms has been successfully created in space on board of a sounding rocket. The MAIUS mission demonstrates that quantum optical sensors can be operated even in harsh environments like space – a prerequi-site for finding answers to the most challenging questions of fundamental physics and an important innovation driver for everyday applications.

According to Albert Einstein's Equivalence Principle, all bodies are accelerated at the same rate by the Earth's gravity, regardless of their properties. This...

Im Focus: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

Breaking the optical bandwidth record of stable pulsed lasers

24.01.2017 | Physics and Astronomy

Choreographing the microRNA-target dance

24.01.2017 | Life Sciences

Spanish scientists create a 3-D bioprinter to print human skin

24.01.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>