It's kind of like a marriage. The system needs its first significant maintenance right now. The project was initiated to take advantage of the California Department of Food and Agriculture's low interest loan program that was available to dairies for the installation of anaerobic digesters as an alternative waste management tool. A plug flow digester was selected because the manure solids could be more easily removed and land application of the liquid manure can be incorporated as part of the irrigation system. The digester itself is installed in a greenhouse that protects it from the elements.
Black plastic covers the digester pit.
The dairy scrapes manure into a mixing pit where water is added as needed to create the proper consistency before it is pumped into the digester. A series of pipes pump water through the digester to heat the manure to around 100 F, activating the methane producing bacteria. In addition to heating the digester, enough hot water is produced for cleaning the milking parlor twice a day, and to heat the Langerwerf's home. The final stage effluent is pumped into a solids separator and applied to the land for fertilizer. The separated solids are used for stall and calf barn bedding, and are sold for mulch to local gardeners.