Guests unveil the UC Davis Renewable Energy Anaerobic Digester (READ) by throwing dinner leftovers into the renewable system. The invention was created by Ruihong Zhang, a professor of biological and agricultural engineering at UC Davis, and will help convert 20,000 tons of wastes into clean energy every year. Photo: Chen Yiming

More than a decade ago, Ruihong Zhang, a professor of biological and agricultural engineering at the University of California, Davis, started working on a problem: How to turn as much organic waste as possible into as much renewable energy as possible.

Recently, the university and Sacramento-based technology partner CleanWorld officially unveiled the UC Davis Renewable Energy Anaerobic Digester (READ) at the campus' former landfill.

The anaerobic digestion technology Zhang invented is being used inside large, white, oxygen-deprived tanks. Bacterial microbes in the tanks feast on campus and community food and yard waste, converting it into clean energy that can then feed into the campus electrical grid.

"It has been the thrust of my research to bring the innovations we made possible at UC Davis to commercial scale," Zhang said. "This technology can change the way we manage our solid waste. It will allow us to be more economically and environmentally sustainable. I am proud and grateful to be a part of the team who helped make this moment a reality."

It is the third commercial biodigester CleanWorld has opened using Zhang's technology within the past two years and is the nation's largest anaerobic biodigester on a college campus.

The system is designed to convert 50 tons of organic waste to 12,000 kilowatt-hours of renewable electricity each day using state-of-the-art generators, diverting 20,000 tons of waste from local landfills each year. The facility is expected to reduce greenhouse gas emissions by 13,500 tons per year.

"It will enable the more than 100 million tons of organic waste each year that is currently being landfilled in the US to be converted to clean energy and soil products," said Michele Wong, CEO of CleanWorld.

"The biodigester is the latest chapter in UC Davis' world-renowned legacy of environmental sustainability," said Linda P.B. Katehi, chancellor of UC Davis.

The READ BioDigester encompasses several of the university's goals: reducing campus waste in a way that makes both economic and environmental sense, generating renewable energy, and transferring technology developed at UC Davis to the commercial marketplace.