Development of a kinetic model to evaluate thiosulfate-driven denitrification and anammox (TDDA) process

• Published in: Water research (Oxford) 2021-06, Vol.198, p.117155, Article 117155
• Main Authors: Deng, Yang-Fan, Tang, Wen-Tao, Huang, Hao, Qian, Jin, Wu, Di, Chen, Guang-Hao
• Format: Article
• Language: English
• Subjects: Anammox; Mathematical modeling; Metagenomics; Partial denitrification; Sulfur-driven denitrification; Thiosulfate oxidation pathway
• ISSN: 0043-1354; 1879-2448
• DOI: 10.1016/j.watres.2021.117155

•A model for thiosulfate-driven denitrification and anammox (TDDA) was developed.•The model was calibrated and validated under different experimental conditions.•A hypothesized branched thiosulfate oxidation pathway was verified by metagenomics.•The model can evaluate the feasibility and operation of the TDDA process. Recently, the integration of sulfur-driven denitrification and anammox process has been extensively studied as a promising alternative nitrogen removal technology. Most of these studies investigated the process feasibility and monitored the community dynamics. However, an in-depth understanding of this new sulfur–nitrogen cycle bioprocess based on mathematical modeling and elucidation of complex interactions among different microorganisms has not yet been achieved. To fill this gap, we developed a kinetic model (with 7 bioprocesses, 12 variables, and 19 parameters) to assess the sulfur(thiosulfate)-driven denitrification and anammox (TDDA) process in a single reactor. The parameters used in this process were separately estimated by fitting the data obtained from the experiments. Then, the model was further validated under different conditions, and the results demonstrated that the developed model could describe the dynamic behaviors of nitrogen and sulfur conversions in the TDDA system. The newly developed branched thiosulfate oxidation model was also verified by conducting a metagenomics analysis. Using the developed model, we i) examined the interactions between sulfur-oxidizing bacteria and anammox bacteria at steady-state conditions with varying substrates to demonstrate the reliability of TDDA, and ii) evaluated the feasibility and operation of the TDDA process in terms of practical implementation. Our results will benefit further exploration of the significance of this novel S-N cycle bioprocess and guide its future applications. [Display omitted]