Starting today, tons of table scraps from the Bay Area’s finest restaurants will be turned into clean, renewable energy at a new UC Davis research and technology demonstration facility.

The “biogas” plant uses bacteria mixed with leftovers. The bugs chew on the leftovers and get the gas. The plant can handle up to 8 tons of garbage a week with each ton produceing enough energy to provide electricity to power 10 average California homes for one day.

If it works as planned, perhaps there will be a time when you clear the table and plop the leftovers into your own onsite personal power plant.

Can’t you hear it now, “Don’t worry about eating everything kids, it won’t go to waste.” A brave new world indeed.

The Biogas Energy Project is the first large-scale demonstration in the United States of a new technology developed in the past eight years by Ruihong Zhang, a UC Davis professor of biological and agricultural engineering. The technology, called an “anaerobic phased solids digester,” has been licensed from the university and adapted for commercial use by Onsite Power Systems Inc.

The goal of this innovative public-private alliance is to divert organic matter — stuff made from plants and animals, such as food waste and yard clippings — away from landfills and into the energy grid. That reduces greenhouse gas emissions from landfills and turns trash into a substantial source of clean energy.

“The new Biogas Energy facility at UC Davis allows us to conduct innovative research on renewable energy sources. By utilizing agricultural and food waste as alternatives to fossil fuels, UC Davis continues the tradition of protecting California’s environment,” said Neal Van Alfen, dean of the College of Agricultural and Environmental Sciences.

Zhang’s system differs from other anaerobic digesters, most of which are in use on municipal wastewater treatment plants and livestock farms, in three key ways:

1: It processes a wider variety of wastes — both solid and liquid — including food scraps, yard trimmings, animal manure and rice straw. More than 5 million tons of food scraps go into California landfills each year.

2: It works faster, turning waste into energy in half the time of other digesters.

3: It produces two clean energy gases — hydrogen and methane. Other digesters produce only methane. The gases can be burned to produce electricity and heat, or to propel cars, trucks and buses.

Zhang has proved in the laboratory on a small scale that in anaerobic, or oxygen-free, conditions, naturally occurring bacteria can quickly convert food and green wastes into hydrogen and methane gases.

Now the challenge is to make the gases in consistently high quality and large volumes over the long term.

Zhang believes it can be done. “My UC Davis students and I have determined the efficient bacterial species and their favorite environmental conditions for turning various wastes into gases,” Zhang said.

“We know what happens with bacteria in 10 to 5,000 gallons of water and waste. Now we expect to see those bacteria perform as well, if not better, when they are in 50,000 to 300,000 gallons.”

Source
UC Davis