Scientific African 16 (2022) e01198 Contents lists available at ScienceDirect Scientific African journal homepage: www.elsevier.com/locate/sciaf The effect of thermochemical pretreatment on anaerobic digestion efficiency of municipal solid waste under mesophilic conditions A. Hajji ∗ , M. Rhachi Mohammed V University in Rabat, Higher School of Technology-Salé, Materials, Energy, and Acoustics Team (MEAT), Crown Prince Street BP 227 Salé - Médina PO Box 11060, Morocco a r t i c l e i n f o Article history: Received 7 October 2021 Revised 1 March 2022 Accepted 21 April 2022 Editor: DR B Gyampoh Keywords: Anaerobic digestion Thermochemical Solubilization Biogas Methane a b s t r a c t Anaerobic digestion is a promising process with many advantages on the environmental and energy level, yet, it remains little exploited, due to the lack of control of the oper- ating parameters of this process, because of the complexity of the biochemical reactions involved. Among the brakes on the development of this sector, we cite the hydrolysis stage, which is the most kinetically limiting phase of the fermentation process. The present work aims to study the effect of thermochemical pretreatment, at temperatures ranging from 55 °C to 65 °C, with a pH ranging from 8 to 12 and a retention time of 6 to 24 h, on the improvement of substrate hydrolysis, while evaluating the solubilization rate and the biogas yield. The results showed that the applied pretreatment was successful in improving the effi- ciency of the anaerobic digestion process, by improving the solubilization rate of the sub- strate, with the greatest rate recorded of 67.1%, which generates a significant increase in the proportion of organic matter that can be converted into biogas. A considerable im- provement of the biogas production and the methane rate was noted for all the exper- iments carried out; the most biogas production of 0.77 mL.g − 1 VS, as well as of the methane rate of 68%, was recorded for the pretreatment conditions at a temperature of 65 °C, a pH of 10 and a retention time of 24 h, which is higher by 180% in biogas, and 19.2% in methane, compared to the case of the non-pretreated substrate. © 2022 The Author(s). Published by Elsevier B.V. on behalf of African Institute of Mathematical Sciences / Next Einstein Initiative. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Introduction Currently, the management of the household and assimilated waste in Morocco presents a major challenge either from a socioeconomic or environmental point of view, given the significant production of solid waste on a national scale, which amounts to almost 6.9 million tons/year, and which is increasing by an annual growth rate of around 1.3%. This growth in the quantities of waste highlights many problems, especially about its landfilling, since waste is composed mostly of organic matter, which is more than 70% of its total mass, with high water content, which favors the excessive production ∗ Corresponding author. E-mail address: amine.hajji@est.um5.ac.ma (A. Hajji). https://doi.org/10.1016/j.sciaf.2022.e01198 2468-2276/© 2022 The Author(s). Published by Elsevier B.V. on behalf of African Institute of Mathematical Sciences / Next Einstein Initiative. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)