A process for the recovery of nitrogen from anaerobically digested liquid waste and for the collection of the nitrogen as nitrate compounds that can be used to produce fertilizer and compost, includes stripping ammonia from anaerobically digested liquid waste, and converting the ammonia into nitrates via nitrification. The stripping gas is heated above ambient atmospheric temperature to improve nitrogen recovery. The heat can be reclaimed by burning gases generated during the anaerobic digestion process.