The ends of carrots from salads, food scraps from vegetables in tacos, coffee grounds, soggy lettuce, and beets and peas from the residence hall food service all have a new life under a programme by a collaboration of departments at Chico State University, Caifornia, according to a report in the Oroville Mercury-Register.

Add some byproducts from a local brewery and wineries and things are getting fired up.

Two programmes using food byproducts include a project to create methane to fuel the energy needs at the University Farm on Hegan Lane, and another to create biodegradable plastic.

Joe Greene, a professor in the mechanical engineering and manufacturing technology department, has been working on the two projects that could lead to a more eco-friendly future.


For the methane project, a concoction of manure, food waste, and in the future green waste, can be mixed into a “recipe” to be placed in a 500-gallon stainless steel vessel that cooks the material down to create methane gas. The professor said it looks somewhat like a wine distillery.

Researchers add nitrogen and microbes that eat starch to produce the methane gas, which is stored in tanks somewhat similar to propane tanks. After more work is done, the plan is to use the gas to power heating for the University Farm buildings.

Currently, 20 percent to 30 percent of the garbage that goes to landfills contains food waste that could be used for programmes like this. The concept is not unlike the scene from the second “Back to the Future” movie, when “Doc Brown” arrives in a car fueled by garbage.

Funding for the project came from the California Energy Commission Public Interest Energy Research program, which funds research into alternative sources of methane. Matching funds came from the California State University Agricultural Research Initiative, for a total of US$300,000.

Both the mechanical engineering department and College of Agriculture are working on the project.

Greene said the hope is to develop systems that can be done on a “farm scale,” so growers can produce their own energy from farm waste.

The project draws on research in the works for about 10 years at UC Davis.

Food to plastic

Even more departments are collaborating on the other project, which will create biodegradable plastic from food waste at the university. This will also incorporate the conversion of beer waste, rice hulls and hopefully white wine waste into lactic acid.

Researchers have isolated a bacterium that digests sugars and converts it to lactic acid. When given the right conditions, the bacteria multiply and are quite efficient.

White wine byproducts are particularly high in sugar, about 25 percent, which is easily digestible by the bacteria.

Lactic acid is commonly found in sour milk products such as yogurt and cottage cheese. This lactic acid can be dehydrated and turned into a biodegradable plastic called polylactide.

Greene explained that a container about 200 gallons is used to make the material for the plastic. Before being used for plastic, the material looks something like a syrup.

Uses might include plastic water bottles or the type of bags used for groceries.

Plastic is a problem because it can clog waterways, fill up landfills and just generally cause an eyesore on the side of the road. Greene explained that bits of plastic can also harm wildlife such as turtles or fish that might eat it.

In March, the San Francisco Board of Supervisors banned non-biodegradable plastic bags. Similar bans have been enacted in Taiwan, Bangladesh and Paris.

Normally biodegradable bags are made from corn or potato starch. Chico State‘‘s project is the first to experiment with these other types of plant material.

“Nobody is really doing what we&ls

Ano da Publicação:
WARMER BULLETIN ENEWS #16-2007-March 20, 2007
Kit Strange/Warmer Bulletin
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