February 25, 2001|By ASCRIBE NEWS SERVICE
LEWISBURG, Pa. - Millions of bacteria are busily converting food waste into methane gas and soil nutrients in a pilot project at the Lycoming County landfill to determine if a full-scale plant could cut by up to 70 percent the amount of organic waste being buried.
The project is directed by Thomas D. DiStefano, associate professor of civil and environmental engineering at Bucknell University, in collaboration with Richard E. Speece, centennial professor of civil and environmental engineering at Vanderbilt University.
Anaerobic process
They have completed a year-long $99,500 feasibility study for the Lycoming County Resource Management Services Inc., which operates the landfill, to test an anaerobic (using no oxygen) process for biodegrading waste. After promising results, the county commissioners have extended their contract for two more years.
"The anaerobic process is a technology that could divert a substantial amount of waste from the landfill and extend the life of the landfill," DiStefano said. "I am not aware of anyone doing this complete process with an anaerobic system."
On the basis of test results, DiStefano hopes to convert 50 percent to 70 percent of the biodegradable waste that is being dumped in landfills into methane gas and soil nutrients, called soil amendments or conditioners, that could be sold commercially. Organic waste constitutes about 25 percent of the waste that comes into the landfill.
DiStefano has been researching anaerobic systems for several years. When county officials suggested that the process be tested at the landfill, he contacted Speece, an expert on anaerobic biotechnology and his mentor as an undergraduate engineering student when both were at Drexel University.
Speece called DiStefano's approach "a novel concept. This is cutting edge, and it is a privilege to be associated with something that probably 10 years down the line will be commonplace."
11 more years
About 1,000 tons of trash and garbage are brought daily to the landfill, which rises to a 200-foot-high hill off U.S. 15.
About 5 million tons of waste, from a six-county area, have been buried on the site, which opened in 1978. At the present rate of dumping, the landfill will last only 11 more years, said Michael D. Hnatin, staff engineer for LCRMS.
In the first year of the project, the anaerobic process treated food waste from an area food-processing plant. "Tests indicated that the process may be amenable to the entire waste stream after recyclables and construction and demolition materials have been removed," DiStefano said.
The project is part of a comprehensive Green Technology Initiatives program the county commissioners have initiated to find ways to bury less waste by recycling more and developing byproducts to sell. Building facilities for the entire program would be a multimillion-dollar project.
If successful, the complete county plan would cut by more than 70 percent the total amount of trash and garbage going into the landfill and could extend the site's life to mid-century, Hnatin said.
The county has begun a recycling system to extract aluminum, plastic and other waste for reuse. Construction of an $8 million recycling facility will begin in June at the 500-acre landfill complex.
Speece said, "Lycoming seems to be out front with this. As you look at public opinion, there's not much alternative. People will not allow anything to be done in their back yard. Where are they going to relocate? Social pressures have to be addressed. Imagine the unthinkable situation where there is no place to put your solid waste. It would be an untenable situation."
The pilot project
For the pilot project, three 10-foot-high, 8-inch-diameter biological reactors were installed. The food processing waste is added to the reactors daily.
One reactor, using recycled water, converts the garbage into simple organic acids, which are then pumped to the second reactor, where the bacteria convert the acid into methane gas. The residue left behind in the reactors is the relatively odorless compound that can be used as a soil nutrient.
The bacteria originally came from the Smucker's plant in Orville, Ohio, which uses them to degrade waste from jelly manufacturing.
"We needed the bacteria as a seed for our reactors. Speece had worked with Smucker's before and contacted them," DiStefano said.
Smucker's provided a couple of 55-gallon drums full of bacteria. The original bacteria keep multiplying.
The methane can be used to produce electricity. The residue of soil nutrients can be used by such businesses as nurseries and golf courses, Hnatin said.
"When applied, the nonchemical nutrients are released slowly into the soil to improve the quality. We're very excited about this," Hnatin said.
