Anammox treatment of high-salinity wastewater at ambient temperature

The present study aims to provide a realistic understanding of how the anammox bacterial community and nitrogen removal performance are affected by increasing salt concentrations at ambient temperature. A laboratory-scale investigation was conducted for 92 days, during which the reactor was fed with synthetic inorganic wastewater composed mainly of NH4+-N and NO2--N. A stable nitrogen removal rate of 4.5 ± 0.1 kg N m−3 day−1 was obtained at a NaCl concentration of 30 g/L, suggesting that the enriched anammox consortium adapted to high salt concentrations. This NRR level is the highest level ever reported at high salt concentration. The addition of salt in the influent was expected to improve the physical properties of the biomass. The anammox bacterium KU2, which was confirmed to adapt to high salt concentrations, was considered to be responsible for the stable nitrogen removal performance. The successful application of anammox technology in this study provides an alternative for the treatment of wastewater containing high concentrations of salt and nitrogen.