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Updated: Sep 30, 2026

Measurement of the Potential Rates of Dissimilatory Nitrate Reduction to Ammonium Based on 14NH4+/15NH4+ Analyses via Sequential Conversion to N2O
Published on: October 7, 2020
Influence of aeration and sludge retention time on ammonium oxidation to nitrite and nitrate
Alfieri Pollice1, Valter Tandoi, Carmela Lestingi
1CNR, Istituto di Ricerca Sulle Acque, Bari, Italy. pollice@area.ba.cnr.it
Abstract:
Partial nitrification to nitrite was reported to be technically feasible and economically favourable, especially when wastewater with high ammonium concentrations or low C/N ratios are treated. Nitritation can be obtained by selectively inhibiting nitrite oxidizing microrganisms through appropriate regulation of the system's pH, temperature, and sludge retention time. In addition to already known methods, the work showed that aeration patterns may play a relevant role too. Nitrification tests were performed in two lab-scale reactors operated under continuous and intermittent aeration, respectively. In both plants, temperature was maintained at 32 degrees C and pH was regulated at 7.2 by providing external buffer capacity when needed. The results showed that partial nitrification to nitrite was steadily obtained under oxygen limitation, independent of the sludge age. Therefore, the aeration pattern is proposed as an alternative parameter to the sludge retention time for controlling ammonium oxidation to nitrite.
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