More than one-third of the food supply in the United States ends up in the trash, according to estimates by the U.S. Department of Agriculture. In California, food waste accounts for about 18 percent of what ends up in the landfill, where it then releases methane as it breaks down.
Looking for ways to make a dent in that volume, in 2013 the Monterey Regional Waste Management District signed on to a pilot program for an anaerobic digester, which accepts a blend of 70-percent food scraps and 30-percent yard clippings, and over the course of 21 days, breaks that down to create methane gas. The gas is used for electricity, which MRWMD would sell to neighboring Monterey One Water. (It’s in contrast to a landfill setting, where gases are not captured for reuse.)
“From a technological and operations standpoint, it worked great,” MRWMD General Manager Tim Flanagan says of the anaerobic digester.
But on Sept. 6, that facility went out of commission.
It’s partly because PG&E put an end to the deal through which the waste district sold power to the neighboring water district three years in, which ended up costing the district about $100,000 a year. Secondly, there’s California Senate Bill 1383, which calls for a 75-percent reduction in organic waste disposal by 2025.
Looking at upping the volume of food scraps MRWMD handles – about 6,000 tons a year – to more like 60,000 tons, Flanagan decided to scrap the old facility. The district will go back to old-fashioned composting in windrows (think industrial-sized backyard compost piles) while looking for bidders to build a larger anaerobic facility, likely at a cost of $30 million to $50 million. One perk of the windrow system is it’s aerobic, meaning air circulates through the food waste so there’s less odor; the anaerobic digester has been a suspected source of a mysterious stink in Marina.
To comply with SB 1383, the district will expand the food it processes from restaurant waste today to residential. “We’re going to have to literally dig through the garbage,” Flanagan says.