Anaerobic lagoon system
This specific system of liquid manure handling is restricted to organized dairy farms, where the flushed manure is directed into an anaerobic lagoon. The first stage of the lagoon system is designed to overflow liquid into a second lagoon or pond designed for liquid storage. Effluent from the storage pond must be utilized for cropland through some type of irrigation system. Sludge accumulated in the anaerobic lagoon contains a significant amount of phosphorus and a small amount of the nitrogen. Sludge is to be removed every 2 to 3 years to keep the lagoon functional. Separation of larger manure solids is often done prior to the waste water entering the lagoon in order to permit accumulation of manure from more cows or to extend the time until cleanout is necessary.