- The Washington Times - Wednesday, October 4, 2006

Waste not, want not.

The notion of turning waste matter into electricity sounds like science fiction, yet several scientists around the world are busy researching ways to do just that.

They are convinced it will be possible to recycle enough human waste, as well as discarded plant matter such as grass and cornstalks, to help reduce a nation’s energy costs.

Among these pioneering professionals is Bruce Logan, director of Penn State University’s Engineering Environmental Institute, who estimates that between 20 and 50 others like him are engaged in projects focused on that goal. However separate the projects, these crusaders in the so-called alternative energy field are determined to use the energy generated by bacteria found in everyday materials and do it on a practical, applicable scale.

“I’m just an environmental engineer who nine years ago decided that energy was going to be one of our greater environment challenges,” says Mr. Logan, 49. His “epiphany moment” happened one cold winter day while walking around State College, Pa., and “seeing house after house lit up and cars driving around. I said to myself, ‘This can’t go on.’ There have been lots of steps since then, of course, many of them involving some very big challenges.

Penn State environmental engineers working under his direction since have showed, for the first time, that a microbial fuel cell (MFC) can generate electricity while simultaneously cleaning the wastewater flushed down the drain and toilet. Mr. Logan, project director, declared in an article posted on www.spacedaily.com two years ago that this development promised eventually to make treatment plant operating costs more affordable.

Gene Peterson, a project officer with the energy efficiency side of the Department of Energy’s National Renewable Energy Laboratory in Golden, Colo., has heard Mr. Logan speak about the project and calls his work promising.

“Wastewater treatment is a big business in this country — as much as $25 billion. Think of it: Dow Chemical, Union Carbide and others. They have a big investment in water treatment.”

Mr. Peterson says he is optimistic about such research as a way of reducing the cost of treatment methods. “It is fascinating,” he says, but it is also just “some of the things academics work on” with results that just may pay off “down the line.”

Microbial fuel cells convert biochemical to electrical energy. Several types of fuel cells exist, but none has yet been designed that is considered cheap and efficient enough to take the place of traditional power sources such as coal and oil, or even water.

The power produced in Penn State’s early experiments was small — only 5 percent of what is needed to run just one mini-Christmas tree light bulb — but it removed 78 percent of the organic matter in the wastewater. That amounted to a breakthrough and potentially a substitute for routine aeration methods normally used in treatment plants. Such methods rely on a large amount of outside energy to be effective.

“Bacteria like those in wastewater naturally produce electrons as they decompose organic material; and electricity is nothing more than flowing electrons,” according to a May issue of Environmental Science & Technology, published by the Washington-based American Chemical Society. “There already are microbial fuel cells, which produce minute amounts of electric current by exploiting electron-producing chemical reactions inside bacteria.”

Funded by both government and private sources, including the National Science Foundation and the U.S. Department of Agriculture, Mr. Logan is aiming to do just that on a large scale. But first, he says, more work must be done to improve the power generation in the MFCs. From there, his team can determine how to make the process more efficient and economical.

Scientists have understood the chemical nature of bacteria since 1911 and have known about fuel cells “for 30 or 40 years,” he says, but few people took them seriously as a source of energy and not at all as an application for wastewater treatment.

He and his colleagues had done an earlier demonstration using cornstalks — which he calls the biggest waste biomass resource in the United States. An estimated 250 million tons is produced annually, he says, of which about 90 percent is left unused.

“Most people have suddenly learned that ethanol can be made from cornstalks,” he said in a report on his earlier effort, which was intended to show how electricity generated by bacteria in the stalks could be an alternative to ethanol. Using a “slightly modified process,” he asserted that it should also be possible to make hydrogen out of ethanol.

But environmentalists long have worried that too much energy is needed to manufacture fossil fuel substitutes such as ethanol and hydrogen. Producing electricity directly is the ideal, says Mr. Logan, since “if we make hydrogen, we need to use some of the electricity we produce.” That doesn’t happen with MFCs because they work by chemical reactions rather than the combustible reactions in carbon-based materials.

A further problem was realizing that only a limited amount of hydrogen can be derived from bacterial fermentation without a power boost of some kind. The challenge then becomes learning how to better manipulate the power source.

So he and his team decided to focus on the challenge of designing and developing new and better MFCs and apply them to recycling wastewater in treatment plants. By eliminating the need for expensive wastewater aeration and using what he calls “direct-air MFCs,” he estimates the country could save billions of dollars.

“The last thing we want to do is run out of clean water and energy,” he says.

The emerging field of nanotechnology — utilizing atoms in their most minuscule form — is of considerable help in his team’s current researches.

“What we are looking at is relying on bacteria that are a thousand nanometers in size. They make their own nanowires that are anything from tens of nanometers wide and a thousand nanometers long,” he says. “So what we have to do is wire the bacteria to surfaces and do a better job on the nano scale to make this happen and [better] understand how this works.”

While the work now largely is done inside a laboratory, it’s not all theoretical experimentation. Several industries, he says, are interested in backing him when the time comes to take the next step, which would be conducting pilot tests using larger systems. He estimates those are “perhaps” a year away.

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