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Simultaneous biological nutrient removal (SBNR) is the biological removal of nitrogen and /or phosphorus in excess of that required for biomass synthesis in biological wastewater treatment systems where defined anaerobic and/or anoxic zones do not exist. The basic hypothesis is that three principal mechanisms might be responsible for SBNR: Bioreactor Macro-Environment, Floc Micro-Environment, and Novel Microorganisms. In this summary paper, our previous results and recent results of others are analyzed to evaluate the original hypothesis. Our previous simulations using the activated sludge models (ASM's) and computational fluid dynamics (CFD) suggest the bioreactor macro-environment and the floc micro-environment contribute significant roles for the SBNR occurring in these systems. CFD analysis revealed that undefined anoxic/anaerobic and aerobic zones exist in the Orbal™ system which allows the presence of PAO. The principal biochemical conversions for nitrogen removal are conventional autotrophic nitrifiers and heterotrophic denitrifiers. The results indicated that novel microorganisms were not substantial contributors to SBNR in the plants studied.

Document Type: Research Article


Publication date: January 1, 2003

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  • 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 These proceedings are not peer reviewed.

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