A wastewater treatment plant in Millbrae, California will now be powered by waste restaurant grease, Chevron Energy Solutions said Thursday.
The $5.5-million wastewater plant will be the first in the United States—and possibly the first in the world—to receive and process inedible grease, said Jim Davis, president of Chevron Energy Solutions.
It’s “a self-funding, purpose-built system that successfully addresses so many challenges simultaneously,” said Dick York, superintendent of the plant, in a press statement. “It’s a complete solution that could be adopted in many cities around the country.”
Grease is difficult to get rid of, and a bane to sewer pipes and storm drains in many cities. According to Chevron, restaurants produce an average of 14 pounds of inedible grease per capita annually—a total of nearly 4.2 billion pounds each year in the United States alone.
A number of companies have tried to find new applications for used grease, such as biodiesel. And some have been successful, but others have had difficulty making it cost-effective to collect the grease and reuse it in a cost-effective manner.
Until Millbrae’s project came along, grease-hauling companies would dump the grease in landfills, where it would eventually emit harmful methane into the atmosphere, Mr. Davis said.
Now, the haulers can bring the grease to the grease-receiving station at the treatment plant, giving them a shorter distance to travel to dump the grease. The haulers will still pay a fee for the grease disposal, which will go into the city’s coffers.
Then, the grease will go into digester tanks at the plant, which contain bacteria and act like a human stomach to digest the grease and turn it into methane gas, a spokesperson said.
The methane gas fuels the plant’s new 250-kilowatt microturbine cogenerator, which turns the methane into electricity for wastewater treatment. The only byproduct from the process is heat, Mr. Davis said.
And that heat is used to warm the digester tanks to their optimum temperature for digestion, body temperature.
“The technology helps create a solution to a number of problems, from disposing of a difficult-to-dispose-of waste stream to creating another renewable source of power to helping to solve a problem for a wastewater treatment plant that is supported by taxpayers, so there’s also a reduction in the taxpayer burden,” Mr. Davis said.
“Every way you look at this solution, it’s a win-win-win for everyone involved,” he added.
Grease is the Word
The Millbrae grease—more than 3,000 gallons of it—is expected to generate about 1.7 million kilowatt hours annually, enough to meet 80 percent of the plant’s power needs and to reduce carbon dioxide emissions by 1.2 million pounds, the equivalent of planting about 170 acres of trees. The project will save the city about $366,000 annually, according to Chevron.
The project began when wastewater treatment officials explained that grease was getting into the plant and causing problems, Mr. Davis said.
Chevron Energy Solutions came up with the solution of installing a grease-receiving station to encourage restaurants and others to bring their grease there to properly dispose of it, instead of illegally pouring it down the drain.
While Mr. Davis doesn’t expect wastewater treatment projects will become a huge part of Chevron Energy Solutions’ business—with energy efficiency and energy conservation projects offering the biggest opportunity—he does think the project will lead to others around the world.
“I think it’s a similar problem for a lot of wastewater treatment plants, and I think the fact that restaurants and hotels have grease disposal issues makes this a very replicable project,” he said. “We’ve had a number of delegates from other countries who have visited us here in the Bay Area and have expressed interest in this project. We’re looking forward to doing many more of them.”
Contact the writer: JKho@RedHerring.com