How is ethanol generally produced using agricultural and/or municipal waste?
Please define what is meant by agricultural and municipal waste.
Are emissions released during the production of this fuel?

Response:

Ethanol is produced from a fermentation/distillation method, similar to that used to produce beverage alcohol. All agricultural crops and residues contain six-carbon sugars or compounds of these sugars. To produce ethanol from grain, the starch portion of the grain is exposed and mixed with water to form a mash. The mash is heated and enzymes are added to separate the fermentable sugars.

The next phase, fermentation, involves the addition of yeast to convert the sugars to ethanol and carbon dioxide. Fermentation produces a mixture called "beer," which contains about 10 percent ethanol and 90 percent water. The "beer" is then boiled in a distillation column to separate the water, resulting in fuel-grade ethanol that is 85 to 95 percent pure. Ethanol production from grain utilizes only the starch.

A variety of highly valued feed co-products, including gluten meal, gluten feed and dried distillers grains, are produced from the remaining protein, minerals, vitamins and fiber and are sold as high-value feed for livestock. In addition to grain, ethanol is also produced today from wood waste, cheese whey, waste sucrose, potato waste, brewery waste, and food and beverage wastes.

The next generation of ethanol production facilities will include production from cellulose and biomass feedstocks. Earlier this year, there was a groundbreaking for a new ethanol production plant in Jennings, Louisiana which, when completed, will produce ethanol from rice hulls and bagasse. Three other plants are currently planned in California that will produce ethanol from rice straw.

One company has plans for production facilities in New York and Alabama to produce ethanol from the biomass portion of municipal solid waste. The plants would reduce capacity problems at wastewater treatment plants and reduce the need for landfills. Many ethanol producers capture carbon dioxide emissions for processing and use in beverages.