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

Sulfur-driven autotrophic denitrification (S0dAD) was employed to remove residual nitrogen from the biological effluent of landfill leachate after partial nitrification and denitrification pretreatment. The performance of S0dAD 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/(m3· 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 S0dAD system. These findings provide insights for advanced nitrogen removal coupling S0dAD with partial nitrification and denitrification process for landfill leachate treatment. • NO x −-N removal efficiency of 97.8 ± 2.0% was achieved via S0dAD under HRT of 0.90 d. • Effluent TN of 8.6 ± 3.8 mg/L was achieved with NRR of 0.12 ± 0.02 kg N/(m3·d). • NO 2 −-N showed 2–4 times higher denitrification rates than NO 3 −-N under coexistence. • S0dAD contributed to over 85% of total NO x −-N removal. • Thiobacillus and Sulfurovum was highly enriched in the S0dAD system. [ABSTRACT FROM AUTHOR]