After the doughnuts are fried and the chicken wings made golden and crispy, what do you do with old cooking oil, the smelly and nasty-looking stuff that remains?
Why, make fuel out of it.
That's what a group of scientists at the Waste Management and Research Center in Champaign are doing.
They're collecting waste oil from the University of Illinois dining halls, whipping up batches of biodiesel and fueling up the center's Ford F-250 pickup truck.
The truck, its decals state, is a vegetarian.
"This is kind of a new direction for us," said Tim Lindsey, manager of the center's pollution prevention program. As part of the Illinois Department of Natural Resources, the Waste Management and Research Center tries to find high-value uses for by-products of manufacturing and industrial processes. It's their first venture into alternative fuels, he said.
Right now they're producing small batches of biodiesel in the center's Champaign laboratory.
"We want to get into bigger applications obviously. We have a large food processing industry in the state," Lindsey said.
Food processing companies like Archer Daniels Midland in Decatur and ACH Foods in Champaign, not to mention restaurants, can produce massive amounts of waste oil. Right now, most dispose of it by paying companies to come to the business, pick up the oil and haul it away.
But companies could be making use of the oil by transforming it into fuel.
Researchers have talked with a range of interested companies – not only processors like ACH Foods, but also trucking companies that pick up waste oil and transportation companies who run buses and passenger shuttles.
The center's staff also plans to work with researchers at the Illinois Natural History Survey on studying ways to produce biodiesel from algae. Algae, it turns out, is the most efficient oil-producing organism on the planet, Lindsey said.
Also, to help spread awareness of the alternative fuel, Waste Management and Research Center scientists will visit schools. Most recently, they held a workshop at Mahomet-Seymour High School and added biodiesel into one of the school buses there.
The center's staff is also willing to work with biodiesel enthusiasts who have or who are interested in cooking up the fuel in their garages or basements.
Biodiesel itself is nontoxic and biodegradable, but the lye-methanol mixture can create toxic fumes.
"You need to educate yourself before you do it," said Rob Guennewig, energy resource engineer with the center.
Biodiesel is produced during a chemical process called transesterification. Essentially, glycerine is removed from the vegetable oil. In order to do this, you need methanol and lye (sodium hydroxide). The oil is heated to speed the reaction.
The result? Glycerine, which can be used in soap, perfumes and cosmetics, and methyl ester, which is straight biodiesel. The glycerine settles on the bottom and the lighter biodiesel rises to the top.
In order to find out how much lye is needed, they run what's called a titration test.
"The longer the cooking oil has been used, the more lye we have to add," Guennewig said.
Researchers plan to investigate catalysts other than lye to use during the production process.
"We'd like to use cleaner chemistry," Lindsey said. For example, using ethanol instead of methanol to make biodiesel.
Biodiesel is not flammable or combustible, Lindsey said. It's as biodegradable as sugar, compared with diesel fuel, which can stay in the soil for a long time, he said.
"However, it has 5 percent less energy than regular diesel. So you don't get quite the acceleration," Lindsey said, referring to driving performance.
Pure biodiesel tends to thicken in cold weather, but fuel additives can solve this problem, Guennewig said.
As far as emissions go, biodiesel has lower particulate and carbon monoxide emissions compared with regular petroleum diesel and virtually no sulfur emissions, Lindsey said.
But it does emit a little more nitrous oxides than regular diesel.