Kroger Uses Spoiled Food for Electricity

Candace Ro, staff writer

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In August, the Natural Resources Defense Council reported that 40% of food in the U.S. goes uneaten which is the equivalent of 20 pounds of food per person per month. The waste is sent to landfills, where it contributes to 25% of the country’s methane emissions. Tons of perfectly ripe fruit, butchered meat, and fresh produce are all gone to waste.

A Kroger company in Compton, California owns land that was destined for a landfill but rerouted to become an energy producer. On May 15, about a 100 people watched as this anaerobic digester system made spoiled foods become electricity.

Stores send food unable to be donated or sold to the facility, where it is dumped into a grinder. The grinder also consumes the cardboard and plastic packaging of foods. This grinded trash is then sent to a pulping machine where inorganic materials such as glass and metal are filtered.

Mike Vriens, Ralph’s vice president of industrial engineering, describes the goop as a “juicy milkshake” of trash. Inside bacteria munch away on the liquid, naturally converting it into methane gas. The gas, which floats to the top of the tank, is pushed out to power three on-site turbine engines.

The 13 million kilowatt-hours of electricity they produce per year could power more than 2,000 California homes over the period, according to Kroger. The program helps Kroger reduce its waste by 150 tons a day. The trash would have been sent to Bakersfield to be composted and hauled away by diesel trucks traveling 500,000 miles a year. This could save up to 110 million dollars per year for the supermarket.

“We’ve had to solve some really critical problems — sanitation, efficiency and reliability issues — that have plagued anaerobic digestion and prevented its wider adoption in the U.S.,” said Nick Whitman, president of Feed Resource Recovery. He added, “Kroger’s new anaerobic digester in Compton may help encourage future installations in more urban areas.”

“Any time we can help mimic nature by recycling nutrients and using them for energy and fertilizer [is for] the better. This is a really cost effective process and provides economic benefits. When people realize they can save money with them, there will more opportunities for reducing waste and generating alternative energy sources,” said AP environmental science teacher Mrs. Solarez.

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