By Pete Zrioka, Arizona State University


Tempe has a grease problem. Waste grease from area restaurants clogs the city’s sewers, diminishing wastewater quality and requiring expensive maintenance. But starting in April, Tempe plans to roll out a new program that could transform grease from a waste product into an energy source.


The Tempe Grease Cooperative is a partnership between downtown restaurants and the city to regulate and improve the collection and disposal of grease, fats and oils. By bringing collection and disposal under one service, the project aims to benefit local businesses while moving toward making the city a cleaner, more sustainable place to live.


Currently, restaurants hire liquid waste contractors to clean out their grease traps and transport the waste to a landfill.


Restaurant owners say the quality of service form some of contractors is substandard because they fail to properly clean grease traps or dump the waste back into the sewer, causing costly maintenance and shortening the longevity of the sewer’s pipes.


The cooperative aims to alleviate these problems by bringing in multiple liquid waste-hauling companies to manage restaurant grease under the supervision of the city, following criteria that address restaurants’ needs.


GPS devices will monitor activity

Under the plan, contractors would clean grease traps correctly and regularly, and the contractors’ trucks would be monitored by GPS devices to ensure the waste is properly disposed. The plan also allows the city to alter the agreement if an opportunity arises to use the grease as an energy source.


“This way, we have total control over the quality of service,” said Tempe Environmental Services Manager David McNeil.


By administering the collection and disposal process, the city can offer restaurants an estimated 25-30 percent discount on the service, and eliminate the restaurants’ regulatory liability.


Instead of visiting a restaurant to check that they’re complying with city ordinance, inspectors visit to check on the quality of work that’s being given to a restaurant as their advocate, said McNeil.


The program’s first year will target downtown Tempe’s high concentration of restaurants and the measurable effects on the sewer system.


Multiple restaurants are already enrolled, including La Bocca Pizzeria & Wine Bar, Canteen Modern Tequila Bar and Monti’s La Casa Vieja.


“Initially, we were very curious as to how the city was going to manage this program,” said Monti’s co-owner Eddie Goitia. “But they laid out a good plan as to what we can do together and we saw it as an opportunity to help out the community as a whole.”


Tempe welcomes restaurants outside of the first-year target area to join the cooperative and hopes to expand the program to the city’s approximately 650 eateries in the future.


“This is the first phase — and we’re capturing the resource,” said McNeil. “Once we have the resource, we’ll have a better feel for how to turn it into energy.”


Sludge digesters are likely first step

During the first year of the program, the city will measure the amount of grease per restaurant to gauge what kind of process is most feasible for energy conversion. Tempe will most likely look into sludge digesters to convert the waste into gas, which can be processed into electricity.


Other processes, such as biofuel conversion, are more costly and require more restaurants than Tempe currently has, according to McNeil.


Michael Nicastro, a sustainability major at Arizona State University, believes the program is a step in the right direction for Tempe.


“This is important for the city of Tempe and shows that the town is proactive,” said Nicastro, who interns at the cooperative, researching cities with similar grease collection programs.


While Tempe won’t be immediately turning grease into a resource, it was the genesis of the program and remains its final goal.


“It’s sitting in the parking lots of every Denny’s and Burger King in the United States and it’s being poorly managed,” said McNeil. “It’s going to emerge as a commodity, and Tempe’s going to lead the way, I think.”

Tempe explores grease as renewable energy source
Local restaurants are working with the city to form a cooperative for liquid waste removal, saving money and keeping city sewers in better shape. Next step: Tur