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Updated: Feb 4, 2026

Estimating Sediment Denitrification Rates Using Cores and N2O Microsensors
Published on: December 6, 2018
Tuning the influent sulfur-to-nitrogen ratio to mitigate nitrous oxide emissions in a sulfite-driven autotrophic
Da Di1, Mi Xue1, Caixia Ping1
1College of Environment and Ecology, Taiyuan University of Technology, Jinzhong 030600, China; Innovation Center for Postgraduate Education in Municipal Engineering of Shanxi Province, Taiyuan 030024, China.
Abstract:
Sulfite-driven autotrophic denitrification (SDAD) is a promising nitrogen removal process, yet its nitrous oxide (N2O) emission remains poorly understood. This study investigated the correlation between N2O emissions and sulfite-to-nitrogen (S/N) molar ratios in an SDAD biofilm reactor. Results showed that a peak total nitrogen removal efficiency (TNRE) of 92.7% was achieved at S/N of 2.6. Crucially, N2O emissions exhibited a non-linear response to S/N ratios. At lower S/N ratios (1.7-2.0), nitrite accumulation and a high genetic potential for N2O production (norB/C-to-nosZ ratio) led to increased emissions. Regulating the S/N ratio to 2.6 minimized the N2O emission factor to 0.5%. Microbial analysis revealed that such an S/N condition favored the enrichment of key autotrophs (Thiobacillus and Sulfurovum) and enhanced nitrogen/sulfur metabolic potential, ensuring efficient N2O reduction via nosZ. This study proposes an effective control strategy for the practical implementation of SDAD, achieving enhanced nitrogen removal while substantially reducing the N2O footprint.
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