Advanced nitrogen removal of sulfur-driven autotrophic denitrification from landfill leachate after partial nitrification and denitrification pretreatment.

Sulfur-driven autotrophic denitrification (SdAD) was employed to remove residual nitrogen from the biological effluent of landfill leachate after partial nitrification and denitrification pretreatment. The performance of SdAD were assessed with various NO-N (NO-N and NO-N) loadings over a 185-day operational period. The results demonstrated that a notable NO-N removal efficiency of 97.8 ± 2.0% was achieved under nitrogen removal rates of 0.12 ± 0.02 kg N/(m· d), leading to total nitrogen concentrations of 8.6 ± 3.8 mg/L in the effluent. Batch experiments revealed competitive utilization of nitrogenous electron acceptors, with NO-N demonstrating 2-4 times higher denitrification rates than NO-N under coexistence conditions. Genus-level microbial community identified that Thiobacillus and Sulfurovum was highly enriched with as key denitrifying bacteria in the SdAD system. These findings provide insights for advanced nitrogen removal coupling SdAD with partial nitrification and denitrification process for landfill leachate treatment.