Michigan Students Convert Fryer Oil to Fuel

ANN ARBOR, Michigan, May 24, 2004 (ENS) - University of Michigan engineering students have discovered that waste grease produced in campus cafeterias that can be used to make biodiesel fuel for campus buses.

During a term project for a course in environmental sustainability, a four student team led by Lisa Colosi and Andres Clarens demonstrated that it is economically and technically feasible to harvest the 10,700 gallons of waste grease produced in the 10 campus dining halls to make a biodiesel fuel.

They produced the fuel in the lab and tested it out on a small university tractor.

The students' vision, "from the fryer to the fuel tank" could save the university $28,000 per year in transportation and disposal costs for the waste food oil, said their instructor, chemical and environmental engineering professor Walter Weber Jr.

Weber said this annual savings could be increased to more than $150,000 by incorporating waste greases from the University Health System cafeterias and area restaurants. The report recommends that the University construct a pilot processing facility on campus to further demonstrate the efficacy of the process.

The University produces nearly 11,000 gallons of waste fat annually that is removed at a cost of 95 cents a gallon. Even if an institution determined it didn't want to produce the biodiesel fuel itself, it could still realize significant savings in disposal costs and perform an environmentally friendly deed by harvesting the waste grease and contracting a vendor to convert it to biodiesel fuel, Weber said.

The university already uses some biodiesel fuel, purchasing 60,000 gallons of soy diesel fuel from a commercial vendor to blend with regular petroleum diesel fuel to make up the 300,000 gallons of combined fuel it uses annually.

"The challenge the students had in this project was to produce a satisfactory or better substitute biodiesel fuel from waste cooking oils," Weber said. "And they did it."

The students collected waste grease from deep fryers in the West Quad cafeteria and mixed it in a tank with potassium hydroxide and methanol to create a reaction that produced a glycerine and fatty acid methyl ester solution.

They then separated the glycerine and heated the residual solution to evaporate excess alcohol and water to produce their biodiesel fuel.

The report the students submitted further suggested that the glycerin by-product of the process could be cured and used to make a biodegradable alternative to commercial soaps for use on campus.

"The project provides an intriguing idea and presents possible options for increasing our waste recycling while yielding a usable product," said Dave Miller, director of U-M's Parking and Transportation Services. "We are exploring the research results and analyzing the potential impact on our existing operations."