Two-stage treatment of the liquid fraction of fermentation residue from agricultural biogas plants by nitrification and subsequent thermal thickening

摘要

This invention describes a method of treating the liquid fraction of a fermentation residue, wherein the liquid fraction of the fermentation residue is first acidified by biochemical oxidation of the ammonia nitrogen contained in it to obtain nitrates and/or nitrites using nitritating and nitrating microorganisms, and subsequently 20-80 % of water content is removed from this liquid fraction of fermentation residue by heat thickening.