Wastewater treatment plant to turn post-consumer food waste into energy

SAN FRANCISCO, CA, July 14, 2009 -- With help from a U.S. Environmental Protection Agency grant, the East Bay Municipal Utility District is pioneering a method of generating renewable energy using food scraps...

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• Recent San Francisco composting law will require new ways to process food scraps

SAN FRANCISCO, CA, July 14, 2009 -- With help from a U.S. Environmental Protection Agency grant, the East Bay Municipal Utility District is pioneering a method of generating renewable energy using food scraps. EBMUD takes food waste from San Francisco and Contra Costa County restaurants and commercial food processors and uses them to produce green renewable energy through anaerobic digestion. The innovative approach decreases food waste sent to landfills and reduces greenhouse gas emissions.

Through anaerobic digestion, bacteria can digest the food waste to produce methane, a valuable energy source when captured. Photo: US EPA.
In light of San Francisco's recently signed mandatory composting law -- the first in the nation -- residents and businesses will begin increasing their composting efforts or finding new and unique ways to divert food scraps from being sent to the landfill. EBMUD's anaerobic digester, in operation since 2004, is leading the way, and currently processes 90 tons per week of post-consumer food waste from restaurants and food processing facilities. The facility plans on increasing the amount of food waste processed to its maximum capacity of 200 tons per day. The process begins when food waste is separated for disposal and pick up. At the EBMUD's main wastewater treatment plant, waste is broken down in large containers called anaerobic digesters. The bacteria inside the digester decompose the food. The digester captures the biogas, and the methane from the biogas powers the treatment plant. Material remaining after the digestion process can be composted and used as a natural fertilizer to help grow food.

Quick facts:

  • In the United States, more than 30 million tons of food waste are sent to landfills annually.
  • Food waste is the second largest category of municipal solid waste in the United States, accounting for 18 percent of the waste stream.
  • In the United States, less than three percent of food waste is diverted from landfills.
  • If 50 percent of food waste in the United States was anaerobically digested, enough electricity would be generated to power approximately 2.5 million homes for a year.
  • Landfills are the second largest source of human-caused methane in the United States, and food waste contributes significantly to landfill methane production.

>> Watch the video on the East Bay Utility District's anaerobic digester
>> Read more about turning food waste into energy

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