EAST LANSING (AP) – Michigan State University trustees Friday authorized construction of a $5 million device that will convert farm and dining hall waste to energy for campus buildings.
The “anaerobic digester” will generate electricity and prevent organic waste from going to landfills, officials said. It also will help meet a broader set of goals that trustees have endorsed for eventually powering the university with renewable energy sources.
The digester is expected to be completed by summer 2013 and will fuel buildings south of the main campus. Waste will decompose at high temperatures in the sealed, oxygen-free tank, producing methane that can be captured and turned into energy.
“Once complete, this system will be the largest on a college campus in the United States,” said Dana Kirk, a specialist with the university’s Department of Biosystems and Agricultural Engineering, which is overseeing the project. “It will be the largest in volume and in energy output.”
Michigan State generates about 21,000 tons of manure and 1,500 tons of food waste annually. Some of what is fed to the digester will come from outside the university.
The tank will hold about 390,000 gallons at 100 degrees for 20-30 days. Naturally occurring microorganisms in livestock manure will break down the mixture into gas and a slurry of partially decomposed organic matter, water and nutrients. Leftover material will be used as fertilizer.
About 20 percent of the energy will be used to keep the process going, and the rest will be used elsewhere.
The university already has a small anaerobic digester for research, but it produces only enough gas to run itself and an adjacent building that supports it.
“Anaerobic digestion has proven to be a feasible technology to convert waste to resource while minimizing negative impact on the environment,” said Ajit Srivastava, chairman of the Department of Biosystems and Agricultural Engineering.
Trustees also voted Friday to adopt a plan drafted by students, faculty and staff for stepping up reliance on renewable energy. It calls for conserving more to reduce greenhouse gas emissions, investing in sustainable energy research and development and becoming a leader in teaching about sustainable energy.
“This is an important step toward a renewable future at MSU,” university President Lou Anna K. Simon said.
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