Performance of a high‐solids anaerobic digestion process under various ammonia concentrations

Ammonia is produced during anaerobic digestion of protein‐containing materials. While ammonia can be utilized by some members of the anaerobic population, excess ammonia can inhibit methanogenesis. High‐solids anaerobic digestion may be especially sensitive to the effects of ammonia overproduction. This study explored the performance of a pilot scale high‐solids anaerobic digestion process under various total ammonia nitrogen (TAN) concentrations. In general the high‐solids digester could operate up to 1000 mg dm−3 without any inhibitory effect. The digester performed best when it was operated at TAN concentrations in the narrow range of 600 to 800 mg dm−3.