Digestion Performance of Various Combinations of Thermophilic and Mesophilic Sludge Digestion Systems

Abstract

Various combinations of single and multi-stage anaerobic and aerobic/anaerobic digestion system were studied to evaluate their solids reduction potential along with capabilities to control sulfur based biosolids odor compounds. All the multi-staged digestion systems removed more volatile solids than the single stage anaerobic digestion systems even at the same overall detention time. However, digestion systems with mesophilic digestion as the final stage showed a much lower headspace organic sulfur contents in the dewatered biosolids than the systems with thermophilic digestion as the final stage. This observation leads to the conclusion that placing a mesophilic anaerobic digestion system at the end of multi-stage digestion systems will enable greater sulfur based odor reduction from dewatered biosolids along with greater solid reduction.

Anaerobic Processes

“…Sludge recirculation between a high-rate ASSR and the aeration basin reduced sludge more effectively and increased performance of treatment. To investigate the effect of aerobic SRT on solids and nitrogen removal, an anaerobic/aerobic sludge digestion system was used to treat a blend of primary and secondary sludge from a municipal wastewater treatment plant (Kim and Novak, 2011b). Aerobic digesters with an SRT of 4 days or longer removed minimum amounts of 11% and 90% of VS and ammonia, respectively, and most…”

Modeling, Instrumentation, Automation, and Optimization of Wastewater Treatment Facilities

“…More than 90% ammonianitrogen and about 50% TKN was removed in the aerobic digester with aeration above 4 days and feeding the aerobic digester once per a day and effluent NOx-N accounted to less than 10% of the ammonia-nitrogen removal. Kim and Novak (2011b)…”