Mainstream partial nitritation/anammox with integrated fixed-film activated sludge: Combined aeration and floc retention time control strategies limit nitrate production.

Implementation of mainstream partial nitritation/anammox (PN/A) can lead to more sustainable and cost-effective sewage treatment. For mainstream PN/A reactor, an integrated fixed-film activated sludge (IFAS) was operated (26 °C). The effects of floccular aerobic sludge retention time (AerSRT), a novel aeration strategy, and N-loading rate were tested to optimize the operational strategy.