Ultra-High Solid Anaerobic Digestion of Sewage Sludge and Ammonia Removal/Recovery

Abstract

 This study investigated ultra-high solid anaerobic digestion (35°C and 20-30days HRT) of sewage sludge and ammonia stripping of digested sludge for the removal/recovery and inhibition of ammonia. At the influent TS 9-11%, the laboratory anaerobic digester was confirmed to perform well, showing VS destruction of 51.3% and gas production of 0.483NL/gVS. At the influent TS 12-15%, the performance was deteriorated, but was recovered when combined with ammonia stripping. The simple stripping device showed the average ammonia removal efficiency of 60-83%, and recovered nitrogen as ammonium sulfate. The results indicate that ultra-high solid anaerobc digestion of sewage sludge is possible up to influent TS 12-15%, as far as proper mixing and ammonia control are provided in digesters.