Energy recovery wastewater treatment plants through anaerobic digestion en en Anaerobic co-digestion (AcoD) helps improve the treatment of organic waste and the recovery of energy in wastewater treatment plants. The current work describes a complete assessment of the various kinetic modeling techniques and the effects of different feedstock compositions on the performance of AcoD based on extensive datasets and sophisticated computational modeling. Eighteen different biomethane potential (BMP) datasets were used to determine several key kinetic parameters, including first-order hydrolysis coefficients (khyd, d-1; 0.08–0.70). The first-order kinetic model was shown to have overwhelmingly better predictive ability (R² > 0.95) and parameter identifiability with respect to the Monod-type models. The incorporation of the modified GISCOD framework with the inhibition function for long-chain fatty acids (LCFA) provided tools for highly accurate simulation of co-digestion dynamics and operational cost reduction of 10.2%. However, feedstock with protein content over 2.5 wt% resulted in significant ammonia inhibition (p-value less than 0.01) and a reduction of 18–22% of methanogenic activity. Multivariate sensitivity analysis showed protein and lipid fractions to be the predominant controls for process stability and methane yield. Quantitative descriptions were able to clarify the results. 284 296 Hamidreza Shiran Department of Environmental Engineering, Aras International Campus University of Tehran, Jolfa Iran hrshiran@gmail.com Gholamreza Nabi Bidhendi Faculty of Environment University of Tehran, Tehran Iran Nasser Mehrdadi Faculty of Environment University of Tehran, Tehran Iran Amirhossein Choopani Department of Environmental Science University of Agricultural Sciences and Natural Resource, Gorgan Iran Anaerobic co-digestion Kinetic modeling Wastewater treatment Biogas production GISCOD model Vol 5 No 4 Paper 2.pdf [1] Metcalf and Eddy, Inc., Wastewater Engineering: Treatment and Resource Recovery, McGraw-Hill Education. (2014). ##[2] A. Gong, G. Wang, X. Qi, Y. He, X. Yang, et al., Energy recovery and saving in municipal wastewater treatment engineering practices, Nat. Sustain. 8 (2025) 112–119. https://doi.org/10.1038/s41893-024-01478-5. ##[3] M. Nasr, E. Ahmadi, N. 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