Household garbage may be blended with post-harvest leftovers from fields, orchards and vineyards to make ethanol and other kinds of bioenergy. Agricultural Research Service scientists are investigating this strategy in their laboratories in Albany, Calif., according to a news release.



In most instances, agricultural wastes like rice straw, almond hulls and the oversize outer leaves of iceberg lettuce will have to be pretreated before being used as a bioenergy resource. That's according to Kevin Holtman, an ARS research chemist who's working out the details of the garbage-to-gas approach.



The garbage, known as municipal solid waste, would also be pretreated, Holtman says.



The garbage would be processed in a jumbo-size autoclave, a device which acts something like a giant pressure cooker to convert the solid waste into gray, lightweight clumps. The pretreated agricultural wastes and autoclaved solid waste would then be transferred to a biofermenter. Yeasts and enzymes would be added to make ethanol.



Holtman and colleagues are determining the best ways to use just water and heat, instead of hazardous chemicals, to pretreat the farm wastes.



The team is collaborating in the research and development venture with Comprehensive Resources, Recovery and Reuse, Inc., or "CR3," of Reno, Nev., and with the Salinas, Calif., Valley Solid Waste Authority.



Besides producing biofuels, the biorefinery would also reduce the volume at landfills and minimize the need for new ones.



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