Novel one-stage reactor configuration for deammonification process: Hydrodynamic evaluation and fast start-up of NITRAMMOX® reactor

Abstract

This study brings an alternative to treat high ammonium-containing wastewater, presenting a new approach exclusively developed to operate one-stage deammonification process called NITRAMMOX®. The reactor was developed to reduce costs and simplify the operation, promising to be favorable to ANAMMOX and AOB. The correlation between reactor configuration and process efficiency were evaluated using the hydrodynamic characterization, flow anomalies identification, oxygen mass transfer efficiency and reactor start-up. NITRAMMOX® quickly acclimated bacteria after inoculation, presenting a 12-day start-up using 6 h-θ, 25 °C. The hydrodynamic results obtained at different superficial gas velocity (0.40 to 31.8 cm min−1) showed a quick oxygen mass transfer and movement, due to the adequate geometric proportion and reactor design. Deviations from ideality do not compromise the ability of the tracer distribution throughout the NITRAMMOX®, indicating great fluid longitudinal dispersion with no dead zones (θr≥θt), no short circuits (Ψ≤0.3) and good hydraulic efficiency (λ > 0.75), approaching the behavior of a complete mixing reactor. The treatment concept by NITRAMMOX® was shown to be suitable for biomass retention and to establish and favor ANAMMOX bacteria, which can achieve high nitrogen removal rates. The reactor can be applied as a new technology for field application in wastewater treatment systems with low C/N ratio.