Evaluation of Simultaneous Nitrification Denitrification in Full Scale SBR Municipal Wastewater Treatment Facility

Examination of the influent and effluent sampling data of the City of Graceville's Wastewater Treatment Facility was investigated to characterize the extent of simultaneous nitrification and denitrification that occurred during the month of September 2008. The results revealed that simultaneous nitrification/denitrification occurred within the Sequential Batch Reactor process during the entire month. Two time periods were investigated as to determine the extent and nature of Nitrogen removal despite significant differences in batch volumes. In contrast to the Orbal processes Nitrogen removal was able to be accomplished totally via simultaneous nitrification/denitrification while meeting what is now considered to be Advanced Wastewater Treatment levels. The low dissolved oxygen concentration did however; impact the settling characteristics of the Activated Sludge. The change in the Phase time structure of the Sequential Batch Reactors in order to accommodate the increased settling time made no impact on the nature of Nitrogen removal via simultaneous nitrification/denitrification. The overall simultaneous nitrification/denitrification efficiency for both basins during September 1-9, 2008 was 97.5% and for September 10-30, 2008 94.5% respectively. Despite the lack of an anoxic period during the treatment time accompanied by 0.50 mg/L or lower dissolved oxygen concentration 90% or greater of the aeration periods. A Total Nitrogen effluent composite monthly average of 2.4 mg/L was observed for the facility.