A kinetic model coupling dynamic environmental factor corrections for the sulfur-boron mud autotrophic denitrification system: calibration and validation.

The existing kinetic models for autotrophic denitrification have limitations in explaining the reaction mechanism of composite filler systems and quantifying the dynamic effects of environmental factors. Therefore, the kinetic model, which explicitly couples the S0 hydrolysis, two-step denitrification process with environmental factor correction functions, was developed for the sulfur-boron mud autotrophic denitrification (SBMAD) system through batch experiments with varied filler ratios and environmental factors (pH, temperature) in this study. And the highest NO3--N removal rate of 27.13 mg/(L·d) was achieved under optimal conditions. On this basis, the key parameters in the model were calibrated using batch experimental data of four groups with different initial NO3--N concentrations and sulfur nitrogen ratios (20 and 200 mg/L NO3--N with 2.8 S0/NO3--N, 50 and 150 mg/L NO3--N with 2.2 S0/NO3--N), obtaining µmax,1 = 0.065 ± 0.017 d- 1, and µmax,2 = 0.052 ± 0.113 d- 1. The model was further validated using four independent experimental data. The results showed that it had reliable predictive performance under different conditions (TIC < 0.25, IoA > 0.91). Therefore, the kinetic model demonstrated reliable predictive performance for simulating the SBMAD process under the investigated batch conditions.