Tempe has discovered a potentially lucrative source of alternative energy in the ickiest of places: restaurant grease traps.
The city is eyeing disgustingly large volumes of grease as something that could generate biofuel — and generate $3 million to $4 million in the next 20 years.
Restaurant grease is mostly a headache to Tempe and other cities now, as some restaurant owners flout rules that they periodically must clean the material sucked out of collectors. The grease clogs sewers and forces expensive maintenance projects.
And some unscrupulous vendors suck out grease, only to drive a few blocks and pour it into a sewer drain.
Tempe is evaluating whether it should offer grease collection services to stop evasive restaurants or grease haulers. It would start with 100 restaurants, which would produce 5,000 gallons a day. The restaurant cluster downtown is the best place to start, Councilwoman Onnie Shekerjian said.
“That’s a good center of grease because we have so many of them,” she said.
Shekerjian said she would prefer restaurants to sign up for city service rather than mandating it. Tempe estimates it could charge 15 percent less than private haulers, which could encourage widespread participation.
If the experiment works, Tempe would consider expanding to serve the city’s 650 restaurants.
Tempe has only identified a few cities that collect grease themselves. The programs reduced costs to restaurants, said David McNeil, Tempe’s environmental services manager.
“They had one less thing to worry about,” he said. “They didn’t have to pick up the phone to find somebody to pick up grease. It just happens.”
The grease issue was forced on Tempe after the Arizona Department of Environmental Quality found too much of the substance was flowing into sewers. Tempe is considering a one-year pilot program starting in early 2012. The effort has the potential to spread across the Valley, McNeil said.
“I think other cities are looking at what we’re doing not only from an energy standpoint, but from a sewage-management standpoint,” he said.
The biggest hurdle for turning the grease into energy is there’s no city-owned facility that can do the job. Tempe is talking to Mesa about processing the grease at a wastewater plant on the southeast corner of the Loop 101 and Loop 202.
The plant is adjacent to the planned Chicago Cubs spring training complex. Mesa is studying whether the grease processing would lead to odor problems.
A $1.2 million plant would save $200,000 a year in energy production and by reducing grease in sewers, said Scott Bouchie, Mesa’s deputy director for environment and sustainability. A $1.7 million configuration would save $400,000 a year.
Further study is needed, said Kathryn Sorensen, the water resources department director.
“Mesa wouldn’t undertake it if it didn’t at least pay for itself and provide some other tangible benefits,” Sorensen said.
Tempe is hoping Mesa makes a decision by 2013. If Mesa decides not to build the grease facility, Tempe would consider building one at a West Valley wastewater treatment plant it owns with several other cities.
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