Temperature Effect on pH and Residence Time as Essential Parameters for Biogas Production: A Review

Abstract

This study presents a systematic review of literature on the influence of temperature on methane production as biogas. A total of 337 scientific documents were collected from the Web of Science database and processed using tools such as Excel, Mendeley, and PRISMA approach literature review tool as PICOT method to identify the articles that best match the objectives of the study by eligibility criteria. The systematic review investigated 25 relevant studies, comparing mesophilic (30–40°C) and thermophilic (50–100°C) conditions. It was found that, although temperature is a determining factor in the efficiency of methanogenesis, its effect is conditioned by variables such as substrate type, residence time, pH, and the pretreatment methods applied. The results show that the mesophilic regime tends to offer greater operational stability, while the thermophilic regime can accelerate anaerobic digestion, but with a higher risk of inhibition by compounds such as free ammonia and volatile fatty acids. The synergy between adequate pretreatments and substrate selection is key to optimizing methane production. This work provides an updated overview of scientific knowledge in this area, identifying gaps and opportunities for future research aimed at the efficient design of thermally optimized anaerobic digestion systems.