A big chunk of the commercial food waste that central Marin County produces could soon be diverted from landfills and converted into methane gas for electricity generation.
The Central Marin Sanitation Agency in San Rafael expects to complete about $250,000 in upgrades to its treatment plant by January to allow it to process food waste and more caustic fats, oil and grease. An on-site power station at the plant already produces enough electricity from sewage-generated methane to run the plant for 12 hours a day. Adding food waste would make the plant's methane digester more efficient.
The last hurdle the program must clear is the increased funding that the Marin Sanitary Service will require to pick up, sort and transport the food waste to the treatment plant.
"What we're doing right now is lining up the funding via the jurisdictions that we have contracts with," said Patty Garbarino, president of Marin Sanitary Service.
Marin Sanitary has submitted a request to the Marin Franchisors Group for a 1.57 percent rate increase for 2013 based on the assumption that a new commercial food waste-to-energy program will begin in mid-2013.
San Rafael, Ross, Larkspur, the county of Marin, Las Gallinas Valley Sanitary District and northern Ross Valley/Sleepy Hollow all belong to the Marin Franchisors Group, which allows them to jointly negotiate their rates with Marin Sanitary. Members of this franchisors group get regular rate reviews
third party, the recycling and solid waste consultant firm Hilton Farnkopf & Hobson of Walnut Creek. Each member receives the same rate increase. Although San Anselmo and Fairfax aren't members, they both contract with Marin Sanitary Service and pay roughly comparable rates.
Garbarino said Marin Sanitary will need to buy two new trucks costing about $330,000 apiece to haul the food waste; she estimates it will cost her company about $458,000 annually to sort contaminants from the food waste -- such as bones, plastic and cutlery -- and to haul the waste to the plant.
Garbarino said the food waste-to-energy program is a response to the Marin County Solid and Hazardous Waste Joint Powers Authority's goal of cutting the amount of Marin waste going to landfills to zero by 2025. Food waste is the largest single source of garbage in California, accounting for 16 percent of the commercial waste stream and 25 percent of residential waste.
In 2008, food waste made up more than 27 percent of the solid waste that Marin Sanitary sent to the Redwood Landfill in Novato, according to a study done by Cal Recovery, a consulting engineering firm based in Concord. The study was commissioned by Marin Sanitary.
The program, however, will only be able to accommodate food waste from restaurants, grocery stores and other commercial establishments, because employees there can be trained to pre-sort waste, Garbarino said. Residential waste is typically too intermingled to effectively sort, she said.
The program will be a money-saver for the Central Marin Sanitation Agency. The conversion of the food waste to methane will result in additional electricity generation and allow the agency to reduce the amount of natural gas it buys from Pacific Gas and Electric Co.
Jason Dow, the sanitation agency's general manager, has estimated the cost savings could eventually amount to $350,000 to $400,000 per year.
"Eventually you could hit those numbers or even exceed them," Dow said. "But to get to those numbers you have to bring in at least 15 tons of food waste, and it will take a little bit of time to get to that level."
At some point, Dow said the electricity generation may exceed the amount needed to operate the plant. He said the sanitation agency could then explore the possibility of selling the excess power to PG&E or the Marin Energy Authority, which serves as its electricity retailer.
Dow and Garbarino have been making presentations at Marin cities' council meetings to update local officials on the program's progress. They were scheduled to speak to the San Rafael City Council on Monday night and will speak to councils in Fairfax and Larkspur on Wednesday night and Ross on Thursday night.
"We're very excited about it," Garbarino said.
Contact Richard Halstead via e-mail at firstname.lastname@example.org ------ (c)2012 The Marin Independent Journal (Novato, Calif.) Visit The Marin Independent Journal (Novato, Calif.) at www.marinij.com Distributed by MCT Information Services