Advanced nitrogen removal from anaerobically pre-treated potato wastewater via partial nitritation-anammox in a continuous fed SBR.

Partial nitritation-anammox was carried out successfully in a continuous fed Sequencing Batch Reactor (cf-SBR), composed of 3 compartments operated in continuous mode. The reactor was operated with floccular biomass (flocs) and biofilm to remove nitrogen from the anaerobic effluent from the potato industry at different nitrogen loading rates (0.16 g TN L d - 0.8 g TN L d). At the maximum nitrogen loading rate (NLR) evaluated the nitrogen removal and ammonia oxidation achieved were 62% and 74% respectively. During the evaluation of the NLR, it was observed an improvement of the characteristics of the sludge, improving the Sludge Volumetric Index (SVI) from 228 to 63 mL g MLSS. Moreover, molecular analysis (qPCR) confirmed the presence of anammox bacteria on the flocs and in the biofilm from the cf-SBR. The results showed the capability of the reactor to carry out the partial nitritation-anammox in the same reactor at pilot scale. The cf-SBR was presented as a suitable and feasible technology for advanced nitrogen removal under partial nitritation and anammox conditions.