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

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 NH 4 + -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.