Dairy cows are very industrious. On average, they produce about 70 pounds of milk a day. Unfortunately, they also produce about 150 pounds a day of manure. Basically, it is an inevitable byproduct of the production of milk.
While manure is a valuable resource for crop production, it has to be moved, stored, and relocated to fields and so forth. This requires equipment, energy and labor and has both economic and environmental costs.
In Tulare County, California – the top dairy producing county in the country – a new manure-to-ethanol plant has recently opened. This is the Calgren Ethanol Biogester in Pixley. It is the first digester in California to transform agricultural waste into cleaner natural gas, which is then used to power an ethanol plant that will produce up to 58 million gallons of ethanol a year. The plant was built by a coalition of companies and was funded in part by a grant from the California Energy Commission.
The plant produces biogas from the manure, recycles water than can be used to irrigate crops, and produces a clean, sterile solid byproduct that can be used as animal bedding. The Calgren plant is a closed-loop, zero-waste system.
This sort of operation is a solution for multiple problems: the need for clean transport fuels, the reduction of agricultural waste, and the desire to improve air quality. As long as cows produce milk, there will be waste. The Biogester plant is a clean and productive way to dispose of cow manure, which can otherwise be a costly and environmentally risky business.
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Manure-to-Energy Plant Launches in San Joaquin Valley
Photo, posted June 24, 2012, courtesy of Ian Barbour via Flickr.
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Earth Wise is a production of WAMC Northeast Public Radio.