NOVELTY - Treating thin stillage from an ethanol production process involves: in a digester (1, 4), treating thin stillage from the ethanol production process using anaerobic digestion to produce an ammonia-rich liquid product; during anaerobic digestion of the thin stillage, with a solids/liquids separation system of the digester, separating the ammonia-rich liquid product from a mixed liquor to produce a permeate; and recycling at least a portion of the permeate from the solids/liquids separation system of the digester directly to the ethanol production process.    USE - For treating thin stillage from an ethanol production process (claimed).    ADVANTAGE - The method enhances the starch to ethanol yeast conversion; improves ethanol production yield; and performs steps better than conventional anaerobic, aerobic, and reverse osmosis processes.    DETAILED DESCRIPTION - Treating thin stillage from an ethanol production process involves: in a digester (1, 4), treating thin stillage from the ethanol production process using anaerobic digestion to produce an ammonia-rich liquid product; during anaerobic digestion of the thin stillage, with a solids/liquids separation system of the digester, separating the ammonia-rich liquid product from a mixed liquor to produce a permeate; and recycling at least a portion of the permeate from the solids/liquids separation system of the digester directly to the ethanol production process. The separating step includes separating the ammonia-rich liquid product from the mixed liquor using membrane technology. The separating step includes separating the ammonia-rich liquid product from the mixed liquor using at least one of microfiltration, ultrafiltration, nanofiltration, and/or reverse osmosis. The recycling step includes recycling permeate directly to the ethanol production process as a substitute for water in one of a liquefaction step, and/or saccharification step, in the ethanol production process. The method further involves handling biogas produced during anaerobic digestion; removing solids produced during anaerobic digestion; and removing ammonia produced during anaerobic digestion including producing struvite from ammonia, and removing the struvite. The method further involves: producing biogas; purifying the biogas to remove H2S to produce an elemental sulfur byproduct; and using the biogas for energy in the ethanol production process. An INDEPENDENT CLAIM is included for reducing energy required to treat thin stillage from an ethanol production process, involving combining a solids/liquid separation process in an anaerobic digestion process; in a digester, treating thin stillage from the ethanol production process using anaerobic digestion to produce an ammonia-rich liquid product; during anaerobic digestion of the thin stillage, with a solids/liquids separation system of the digester, separating the ammonia-rich liquid product from a mixed liquor to produce a permeate; and recycling at least a portion of the permeate from the solids/liquids separation system of the digester directly to the ethanol production process.    DESCRIPTION OF DRAWING(S) - The figure shows schematic view illustrating a pilot anaerobic treatment process for digesting thin stillage.    Digester (1, 4)    Draft tube (2)    Digital thermometer (3)    Flow meter (5)    Additional port (6)    Centrifugal pump (7)    Ultra filtration membrane (8)    Retentate (9)    Heat exchanger (10)    Nozzle (11)    Diaphragm pump (15)