Controlling nitritation in a continuous split-feed/aeration biofilm nitrifying bioreactor. (September 2019)

• Record Type: Journal Article
• Authors: Dawas, Anwar; Abu-Salih, Samy; Sabbah, Isam; Nejidat, Ali; Dosoretz, Carlos G.
• Is Part Of: Bioresource technology. Volume 288(2019)
• Publication Date: 2019-09
• Subjects: Nitritation control -- Up-flow fixed bed reactor -- Recirculation ratio -- Dissolved oxygen -- Numerical simulation; Biomass -- Periodicals; Biomass energy -- Periodicals; Bioremediation -- Periodicals; Agricultural wastes -- Periodicals; Factory and trade waste -- Periodicals; Organic wastes -- Periodicals; Bioénergie -- Périodiques; Déchets agricoles -- Périodiques; Déchets industriels -- Périodiques; Déchets organiques -- Périodiques; Déchets (Combustible) -- Périodiques; 662.88
• DOI: 10.1016/j.biortech.2019.121599
• Languages: English
• ISSNs: 0960-8524

Abstract

Highlights: Split-feed/aeration operating mode controls DO profile in fixed-bed biofilm reactor. Stable partial nitritation with minimal nitrate accumulation was achieved at R = 4–6. Nitrosomonas and Nitrospira were the dominant AOB and NOB genus in the reactor. A COMSOL-based numerical model successfully predicts the N-species and DO profiles. The model showed good sensitivity to the biofilm-intrinsic oxygen uptake parameters. Abstract: This study explored the stability of partial ammonium oxidation at low feed concentration (50 g N/m 3 ), 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 NH 4 + oxidized to NO 2 - with <5% NO 3 - 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 oxidizing archaea. A numerical model for predicting the concentration of the nitrogen species and DO was formulated. The model successfully predicted the experimental results and displayed good sensitivity to intrinsic oxygen uptake parameters. The proposed numerical model can serve both as an operational and design tool.