The development of a reverse anammox sequencing partial nitrification process for simultaneous nitrogen and COD removal from wastewater

•A novel reverse anammox–partial nitrification nitrogen removal process was developed.•The steady nitrogen removal rate was obtained at 0.92–1.03 kg N m−3 day−1.•The synergistic effect of anammox bacteria, AOB and heterotrophic bacteria was found in a fixed bed.

In order to achieve simultaneous removal of nitrogenous and organic pollutants, a novel reverse anammox–partial nitrification nitrogen removal process was developed. During steady operation, the maximum nitrogen and COD (chemical oxygen demand) removal efficiencies were over 90%, with influent NH4+-N and COD concentrations of 300 and 100 mg L−1. The optimum recycle ratio of Membrane bioreactor (MBR for partial nitrification) and fixed bed reactor (anammox) for this process was recommended as 3 due to increasingly larger recycle ratio caused slight increase in TN (total nitrogen) removal efficiency. Additionally, the steady nitrogen removal rate was obtained at 0.92–1.03 kg N m−3 day−1. Considering its great potential in nitrogen removal, this reverse process will be revealing for the study of anammox technique.

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