Research on DN-PN/A coupled treatment of low ammonia nitrogen electroplating tail water
A pilot-scale continuous-flow denitrification partial nitrification-anaerobic ammonia oxidation(Anammox)multi-unit reactor was constructed to treat the electroplating tail wastewater.The pre-denitrification reactor demonstrated total inorganic nitrogen(TIN)and chemical oxygen demand(COD)removal efficiencies of(29.96±10.37)%and(73.33±9.6)%,respectively,with substantial removal of soluble organics to reduce pollutant loads in subsequent processes.The partial nitrification reactor confirmed that the zeolite packing method effectively achieved stable partial nitrification,yielding a nitrogen accumulation rate of(87.73±22.28)%.During long-term operation,it will be affected by scale,and its performance can be restored after scale removal.The Anammox reactor,as the primary nitrogen removal stage,maintained a TIN removal efficiency of(41.25±14.46)%even during partial nitrification instability,relying on the cooperative effects of ammonia-oxidizing bacterium(AOB),denitrifying bacteria(DNB),and anammox bacteria(AnAOB).High-throughput sequencing identified Nitrosomonas(AOB),in the partial nitrification reactor,with a relative abundance of 5.45%,and Candidatus Anammoglobus(AnAOB),with a relative abundance of 25.91%.These findings provide both theoretical and practical foundations for applying the Anammox process in engineering contexts.