US Patent 9751787 Anaerobic digesting systems and methods for processing animal waste

A digester system for digesting feed material comprises a digester tank, a thickener, and a seal system. The digester tank generates a first digested material and biogas from the feed material. The thickener is operatively connected to the digester tank to remove a second digested material from the feed material to alter a solid content of the feed material in the digester tank. The seal system substantially prevents the thickener from removing biogas from the feed material with the second digested material.