The U. S. is moving that way, but it' s ever so much slower. Koelsch said farmers interested in using plug-flow and other anaerobic systems need to educate themselves before seriously considering using the techniques. Other farms, such as hog and egg-layer chicken operations, can use anaerobic digesters to fully utilize their animal waste. But each type of operation needs a system specifically tailored to meet its needs. Linda Langerwerf, who farms near Durham, Calif., said methane from her system powers a generator to produce electricity.
Water is heated in the process.
The hot water, in turn, is used to heat the slurry of manure in her digester, which helps the process. She uses the excess hot water in her milking operation and in her home, including a radiator system that heats the home in the winter. Solids that remain are used for bedding material for cows and sold to local gardeners. Although Langerwerf said the plug-flow digester on her farm has helped her operation, there are some limiting factors. Her system was financed by a low-interest loan.