A new purification system for recycling food waste is being used by the Los Angeles County Sanitation Districts to produce renewable natural gas for vehicles, it was announced Tuesday.

The biogas purification system makes use of dinner scraps, spoiled fruit and vegetables from grocery stores and restaurants to create fuel, said Robert C. Ferrante, chief engineer and general manager for the Sanitation Districts.

“We’ve been converting food waste into electricity for over six years. With this new biogas purification system, we now also produce renewable natural gas that is used to fuel vehicles like cars, buses and trucks,” Ferrante said. “We know that many cities are grappling with how to meet state requirements for recycling food waste, and (we) are pleased to offer a complete and cost-effective solution.”

Here’s how it works:

— the Sanitation Districts’ waste haulers collect food waste placed in bins by customers;

— loads of food waste are delivered to the Sanitation Districts’ Puente Hills Materials Recovery Facility in Whittier;

— at the Whittier facility, contaminants such as plastic bags and forks are removed and the food waste is blended into slurry; and

— the slurry goes to a wastewater treatment plant in Carson, where it is added to the plant’s digesters, which are large, sealed tanks where microorganisms convert food waste and wastewater solids into biogas.

Some of that biogas is being sent to the Sanitation Districts’ power plant to be converted to electricity. The rest is going through the new purification system to make fuel-grade renewable natural gas, with the system able to produce the renewable natural gas equivalent of 2,000 gallons of gasoline per day.

The renewable natural gas is dispensed at the Sanitation Districts’ nearby fueling station that is open to the public.

“Because the Sanitation Districts manage both solid waste and wastewater, we already had most of the infrastructure needed for food waste recycling. We also received a grant from the California Energy Commission that helped fund the new biogas purification facility. As a result, we were able to complete our system relatively inexpensively and pass those savings onto our customers,” said Bob Asgian, head of the Sanitation Districts’ Solid Waste Management Department. “Use of our system has been steadily growing and we have additional available capacity to help more cities.”

The Sanitation Districts serve the wastewater and solid waste management needs of 78 cities and unincorporated areas in Los Angeles County.

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