Recent research in our laboratory has focused on combined anaerobic/aerobic digestion. There are many advantages to combined anaerobic/aerobic digestion and these include better solids reduction, improved sludge dewatering properties and reduction of nitrogen. In this study, an additional
anaerobic digestion step was provided. Solids from the aerobic digester were thickened, the centrate discharged and the concentrated solids recycled back to the anaerobic unit. This is called anaerobic/aerobic/anaerobic digestion. The addition of the recycled sludge does not increase the reactor
size but does require a separate recycle step. Combined anaerobic/aerobic/anaerobic digestion resulted in additional solids reduction, from 50% for conventional digestion to 62% for anaerobic/aerobic and 70% for anaerobic/aerobic/anaerobic.Total Kjeldahl nitrogen (TKN) removal was greater
than 60% for both the anaerobic/aerobic and anaerobic/aerobic/anaerobic digesters. The combined anaerobic/aerobic and anaerobic/aerobic/anaerobic also resulted in lower polymer conditioning requirements compared to anaerobic digestion alone and lower organic sulfur odors were generated from
the biosolids digested under the combined systems.
Proceedings of the Water Environment Federation is an archive of papers published in the proceedings of the annual Water Environment Federation® Technical Exhibition and Conference (WEFTEC® ) and specialty conferences held since the year 2000. These proceedings are not peer reviewed. WEF Members: Sign in (right panel) with your IngentaConnect user name and password to receive complimentary access.