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Updated: Jan 21, 2026

Application of Design Aspects in Uniaxial Loading Machine Development
Published on: September 19, 2018
Partial nitritation at elevated loading rates: design curves and biofilm characteristics
Alexander Schopf1, Robert Delatolla2, Kathlyn M Kirkwood3
1Department of Civil Engineering, Ottawa-Carleton Institute for Environmental Engineering, University of Ottawa, Ottawa, Canada.
Abstract:
There is a need to develop low operational intensity, cost-effective, and small-footprint systems to treat wastewater. Partial nitritation has been studied using a variety of control strategies, however, a gap in passive operation is evident. This research investigates the use of elevated loading rates as a strategy for achieving low operational intensity partial nitritation in a moving bed biofilm reactor (MBBR) system. The effects of loading rates on nitrification kinetics and biofilm characteristics were determined at elevated, steady dissolved oxygen concentrations between 5.5 and 7.0 mg O2/L and ambient temperatures between 19 and 21 °C. Four elevated loading rates (3, 4, 5 and 6.5 g NH4+-N/m2 days) were tested with a distinct shift in kinetics being observed towards nitritation at elevated loadings. Complete partial nitritation (100% nitrite production) was achieved at 6.5 g NH4+-N/m2 days, likely due to thick biofilm (572 µm) and elevated NH4+-N load, which resulted in suppression of nitrite oxidation.
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