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Dr. Craig Frear, WSU Extension, explains to one of the tour break out groups how solids are extracted from liquid leaving the digester to produce a fibrous product that makes a good soil amendment and a finer solids that is a good source of fertilizer, particularly phosphorus.
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The Edaleen and Vander Haak dairies near Lynden attracted 80 manure resource recovery experts from the biennial Waste to Worth Conference for tours of their anaerobic digestion systems, organized by WSU Animal Scientist Joe Harrison. They saw firsthand how these manure digesters convert dairy cow manure into electricity and usable by-products such as compost, peat moss and nutrient-rich fertilizers. There are currently seven anaerobic digestion systems in the Whatcom region.
WSU Assistant Professor Craig Frear, who specializes in digestion systems and related manure management technologies at the WSU Center for Sustaining Agriculture and Natural Resources, led several of the tours along with dairy farm staff and representatives of Regenis Corporation (suppliers of operations and maintenance for digesters). "It was an eye-opener for these experts to see how dairy producers are doing some cutting edge work with digesters, producing not only electricity but other by-products - and getting carbon credits as well," Frear said.
Experts learned how the Vander Haak dairy invested in the state's first manure digester in 2005, and since then have increased power output by 25 percent - enough to power 400 Whatcom homes every year. They have also retooled the digester to reduce odor, and now take commercial food waste as well as cow manure to make nutrient-rich fertilizers. Edaleen Dairy has been in business for 40 years and continues to embrace new technologies. Their digester was commissioned in 2012, producing 750 KW of electrical energy -sufficient to power about 700 homes.
Dr. Frear added that"Incorporation of anaerobic digesters on smaller dairies of, say 400 cows or less, is very difficult due to economics; but researchers are looking at other valued means for processing manure on these smaller dairies, such as innovative compost systems that harness the compost heat and carbon dioxide for installation of greenhouses and the extra produce and revenue they can yield." Read more..
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