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

Sulfur-driven autotrophic denitrification (S 0 dAD) was employed to remove residual nitrogen from the biological effluent of landfill leachate after partial nitrification and denitrification pretreatment. The performance of S 0 dAD were assessed with various NO x--N (NO 2--N and NO 3--N) loadings over a 185-day operational period. The results demonstrated that a notable NO x--N removal efficiency of 97.8 +/- 2.0% was achieved under nitrogen removal rates of 0.12 +/- 0.02 kg N/(m 3 & sdot; 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 2--N demonstrating 2 - 4 times higher denitrification rates than NO 3--N under coexistence conditions. Genus-level microbial community identified that Thiobacillus and Sulfurovum was highly enriched with as key denitrifying bacteria in the S 0 dAD system. These findings provide insights for advanced nitrogen removal coupling S 0 dAD with partial nitrification and denitrification process for landfill leachate treatment.