Application of Contois, Tessier, and first-order kinetics for modeling and simulation of a composting decomposition process

An integrated model was developed by associating separate degradation kinetics for an array of degradations during a decomposition process, which was considered as a novelty of this study. The raw composting material was divided into soluble, hemi-/cellulose, lignin, NBVS, ash, water, and free air-space. Considering their specific capabilities of expressing certain degradation phenomenon, Contois, Tessier (an extension to Monod kinetic), and first-order kinetics were employed to calculate the biochemical rates. It was found that the degradation of soluble substrate was relatively faster which could reach a maximum rate of about 0.4 per hour. The hydrolysis of lignin was rate-limiting with a maximum rate of about 0.04 per hour. The dry-based peak concentrations of soluble, hemi-/cellulose and lignin degraders were about 0.9, 0.2 and 0.3 kg m−3, respectively. Model developed, as a platform, allows degradation simulation of composting material that could be separated into the different components used in this study.