In 2009, the Bach digester became an addition to Bach Farms in Dorchester, WI. In 2013, it expanded to include a second digester vessel (see next IFES case). Together they use manure produced by the dairy to produce methane gas that powers two 300 KW generators. The resulting electricity is enough to power 450 homes in the surrounding area.
The digester is a mixed-tank variety, where the manure flows through gravity from the freestall barns through 24-inch pipes into a tank called the “mix tank.” Along with this liquid manure, two 700 bushel box spreaders full of dry bedding pack, spoiled feed waste, and manger cleanings are added to the mix tank, which holds 100,000 gallons of manure waste.
Bach Farms added a separate 10,000 gallon substrate tank to their digester for storage space to allow for controlling additional substrate added to the mix tank.
The heat that is produced by the engines is used by the farm to heat the water that is used throughout the farm. In addition to heating the entire parlor, house, shops and barns, the waste heat is also used in the digester wash bay building to heat the wash water and the building itself, and in the pasteurizer to pasteurize milk for feeding calves.
IFES Number: 322
Main Products: Dairy
Size of Firm: Farm Scale
Operational Status: Operational
Year Installed: 2010
Energy Uses: Electricity, Boiler or furnace fuel
Methane Emissions Reductions: 6478