Waste cooking oil to power BGSU campus mowers

BOWLING GREEN, O.—Next summer at Bowling Green State University, when the grass is green and the lawn mowers go about their work, campus pedestrians might notice the enticing smell of . . . doughnuts. Thanks to the work of two former environmental studies classes; support from Duane Hamilton, director of campus services in facilities services, and a grant from the Ohio Department of Natural Resources, BGSU mowers will begin to run on used cooking oil from the dining halls.

The project has been in the works since 2005, when Dr. Enrique Gomezdelcampo’s Environmental Studies 402 class, for its capstone project, prepared an environmental impact statement on “Limiting Emissions from the Campus Maintenance and Small Equipment Fleet.” Last spring’s 402 class concentrated on the use of “Waste Vegetable Oil as Fuel for Campus Lawn Mowers.”

Working alongside the facilities services department, the class researched the feasibility of recycling the vegetable oil produced in the dining halls. “They asked the questions: How much fuel do we need? How would you go about it? How would we filter the oil? The students did all that, and they figured the costs,” said Gomezdelcampo, an assistant professor of environmental studies.

With a $50,000 ODNR grant, signed last July, the University can now proceed with the conversion of the first mower and purchase a holding tank and collection drums—which are now supplied by an outside company—along with building a filtration system for the oil.

The plan is to buy drums made from recycled materials and label them. “We want to have signage everywhere, for a kind of passive education,” Hamilton said, adding that the state grant is part of a program especially for universities. “I think it’s going to be fun, and I think we’re going to find more and more people who want to get involved.”

Hamilton is pleased the project has finally gotten off the ground. “We’ve talked about it jokingly for 20 years, and it has been done on other campuses. For years, we paid a company to haul away our used cooking oil. Then they began hauling it for free because they could sell it to others for fuel.

“From a sustainability point of view, why pay to get rid of something that we could use, and then pay for another source of fuel?”

The environmental impact of the conversion would also be substantial, the students found. “The use of waste vegetable oil (WVO) in all the current lawn mowers would reduce their emissions by 43 percent in carbon monoxide, 56 percent in hydrocarbons, and 55 percent in particulates,” according to their report.

The process will begin this winter with the conversion of one riding mower, which will be accomplished by facilities staff. Overseeing the work is Scott Euler, manager of grounds and solid waste, who has been involved with the project from the beginning, working with the students to teach them about the equipment. “We believe that with our small diesel engines, we have good success potential,” Hamilton said.

Noting that diesel engines were originally designed to also run on vegetable oil, Gomezdelcampo said the process of converting to WVO is fairly straightforward and does not require any chemical mixing. “We will test it in-house and if it works well, eventually we could convert all our small diesel-powered trucks and tractors,” he said. “We generate enough waste cooking oil.

“It’s a parallel system,” he explained. The lawnmower will retain its original diesel line and tank, which will be used for startup and ending because of the WVO’s higher viscosity and surface tension. Once the engine is warmed with the diesel, the driver will switch over to the WVO tank, which will deliver the cooking oil in the same fuel line as the diesel. Special tanks are being fabricated for the WVO. The last step is to turn back to diesel to flush out the fuel lines.

Slightly more cooking oil is needed than diesel, both for miles per gallon and BTUs, Hamilton said, but “the campus gets more than enough from the dining facilities.”

Facilities staff will pick up the drums from the dining halls and filter the oil. “Enrique’s class did a great job of researching various filtration methods to find the one that will work for us,” Hamilton said.

While the mower fuel is most heavily used during the summer months, the cooking oil is produced mainly throughout the academic year, he said. Fortunately, it can be stockpiled through the winter for the long, March-November mowing season. In autumn, the mowers are used to mulch leaves for a “great, free fertilizer,” Hamilton added.

Gomezdelcampo said he has been contacting the original class members to let them know their work is coming to fruition. “The students really enjoyed the project,” he said.

In their summary of the environmental impact statement, the 2005 class said that by “utilizing alternative fuels and equipment, BGSU would be able to decrease its environmental impact footprint, increase the efficiency of current equipment and become an example for other universities. The use of these alternatives will also reduce fuel and maintenance costs and contribute to a better quality of life for campus and the surrounding area.” It also would allow the University to become a leader in the “move toward a more environmentally conscious world.”

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(Posted November 21, 2008 )