Clogging up sewers and complicating wastewater treatment, used cooking oil can be the bane of city and county public works departments. Meanwhile, rising gasoline prices are driving many fleet managers to convert their vehicles to alternative fuels, such as biodiesel. To address both problems, some local governments are collecting used grease from restaurants and residents and converting it into biodiesel to power their vehicles.

Grease that is not properly discarded can cause expensive problems for a city's sewer system because it becomes gelatinous and causes pipe blockages. The majority of Hoover, Ala.'s sewer service calls are for problems caused by grease. “The average sewer call runs us anywhere from $1,500 to $2,500 [or more if the sewer backs up into nearby homes],” says Fleet Management Director David Lindon.

For more than three months, the Hoover Fleet Management Department has been collecting used cooking grease from restaurants and converting it to fuel as part of a pilot program. “We're running 10 vehicles on that now,” Lindon says.

Ultimately, the city plans to expand the program to include grease collected from homes. Residents will be given containers for their used cooking oil, and the city will establish central locations for collection sites. “We're actually going to go after the grease at home, so the homeowner doesn't put it in the yard, in the trash can or down the drain,” Lindon says.

Kalamazoo, Mich., is working with faculty members at West Michigan University (WMU) who are constructing a small-scale biodiesel production facility at the city's Wastewater Reclamation Plant. “[The program is] going to be a double win from the standpoint of not only providing biodiesel, but preventing these waste-trapped greases from entering the sewer system,” says Bill Schomisch, transportation director for the Kalamazoo bus fleet.

The WMU plant will open in the fall. In the meantime, the city already has begun to convert its entire bus fleet to B5 — a mixture of 95 percent ultra-low sulfur diesel and 5 percent biodiesel — and buy fuel from a local distributor. Schomisch's department will begin accepting fuel from the WMU facility when it becomes available. “[WMU] was going to be able to offer us either at-market or less-than-market costs because they're a non-profit,” Schomisch says.

Santa Cruz, Calif.-based non-profit Ecology Action, which supports a variety of conservation programs through education services and technical support, began a program in 2006 to study the commercial viability of using biodiesel made from grease to power city fleets. Funded by the Environmental Protection Agency (EPA), the program is working with a biodiesel production facility in Gonzales, Calif., that is producing fuel using processed grease from companies that have collection contracts with area restaurants. Santa Cruz and Santa Cruz County are using the fuel in their fleets, says Michael Drury, program director for Ecology Action's energy group.

Cities that are considering starting a grease-to-biodiesel program must account for many variables, such as location of grease suppliers and the quality of the resulting fuel to judge whether it is economically practical, Drury says.

Ecology Action plans to use information from the study to produce a guidebook for cities and counties interested in producing biodiesel from cooking oil. Drury gets many calls from local governments that are considering similar programs, but he says fleet managers should not rely on biodiesel from grease to meet all of their alternative fuel needs. “It's not going to solve everybody's problem,” Drury says. “I have to say that the conclusion I've come to is that it's a terrific way to process a waste stream into a valuable product.”