Integrating thermodynamics and mathematical modelling to investigate the stoichiometry and kinetics of sulphide oxidation-nitrate reduction with a special focus on partial autotrophic denitrification.

In the present study, the stoichiometry of the Sulphur Oxidizing-Nitrate Reducing (SO-NR) process, with a focus on Partial Autotrophic Denitrification (PAD), has been evaluated through a thermodynamic-based study whereas a model-based approach has been adopted to assess process kinetics. Experimental data on process performance and biomass yields were available from a previous work achieving efficient PAD, where a biomass yield of 0.113 gVSS/gS was estimated.

Successful sulphide-driven partial denitrification: Efficiency, stability and resilience in SRT-controlled conditions.

Partial denitrification is emerging as a valuable solution for NO supply in Anammox systems. When reduced sulphur compounds are used as electron donors, S-driven Partial Autotrophic Denitrification (PAD) can also be achieved, allowing for an integrated autotrophic nitrogen (N) and sulphur (S) removal from liquid and gaseous streams. The aim of the present work was to maximise NO reduction to NO coupled with complete HS oxidation, by the selective control of influent S/N ratio and sludge retention time (SRT).