Controlling nitritation in a continuous split-feed/aeration biofilm nitrifying bioreactor

Dawas, A
Abu-Salih, S
Sabbah, I
Nejidat, A
Dosoretz, CG

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Publication date

September 2019

DOI

10.1016/j.biortech.2019.121599

Publisher

Elsevier BV

Journal

Bioresource Technology

Abstract

© 2019 Elsevier Ltd This study explored the stability of partial ammonium oxidation at low feed concentration (50 g N/m3), suitable for anammox process, in continuous fixed bed up-flow biofilm reactors with external recirculation-aeration. The reactors, filled with crushed basalt, were fed with synthetic medium at 20–25 °C at constant flow-rate with limiting dissolved oxygen concentration controlled by the recirculation ratio (R). Successful nitritation was achieved at R ≅ 4–6 with approx. 50% of NH4+ oxidized to NO2- with <5% NO3-accumulation. q-PCR analysis along the reactor showed ammonia oxidizing bacteria being the prevalent nitrifiers over the three-fourths of the bed in the flow direction, negligible denitrifiers and absent ammonium ...