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ANATOMY OF A DEAL
Michigan hog grower, via grants which enabled a loan, puts together a project to design and implement an anaerobic digester to process the farm's manure.
LENDERS are generally well disposed to projects that diversify revenues while lowering costs and mitigating risks. Add a ready source of equity and you are well on the way toward financing a project that is a win-win proposition for the lender and the project developer. Such is the case with the anaerobic digester project at Geerlings Hillside Farm (GHF).
The Geerlings's 8,000-head hog farm is located in Allegan County in southwestern Michigan. Farmers in the area face restrictions on field-applying untreated manure. Runoff from agricultural operations and other land-based activities have resulted in nutrient overloading and sediment pollution in the local Little Rabbit River watershed.
Because of the restrictions, area livestock operations are forced to haul manure that can't be field-applied locally to farms where manure nutrients are needed. Farmers also face sharp increases in residential development near their facilities, resulting in complaints about manure odors.
To deal with waste and nutrient management issues, the Geerlings teamed with Fennville, Michigan-based Phase 3 Renewables to design and implement an anaerobic digester (AD) to process the farm's hog manure. The innovative system includes equipment to produce pelleted fertilizer and irrigation water through further post treatment of the liquid digester effluent.
The post treatment process coupled with the AD system removes more than 90 percent of the nutrients from the liquid effluent. The resulting liquid contains very low levels of nitrogen and phosphorous that fall within the nutrient management restriction, permitting the water to be used for irrigation.
Three local farms, which are too small to justify on-site AD systems, are partnering with GHF to contribute manure to the system. In total, the digester will process over 8 million gallons of manure from 16,000 hogs and 400 heifers, and produce over 28 million cubic feet of biogas annually.
THE PROCESS
The digester is housed in a 65-foot diameter complete mix-stir tank operating under anaerobic conditions with a capacity of just over 550,000 gallons. Temperatures in the reactor range from 98° to 104°F, with a retention time of 24 to 25 days.
Manure from pits beneath the barns housing...