Modelling composting as a microbial ecosystem: a simulation approach

The article presents a mathematical formulation of the physical and biological laws that govern the composting process. The model of the composting ecosystem includes mass transfer, heat transfer, and conversion of organic matter into CO2 and humic substances. The first trophic level is described as a consumption of four substrates by a 4-component microflora, with equations of microbial growth kinetics that consider (a) the coexistence of specialists and generalists among consumers, and (b) specific conditions for the decay of lignin. The model can predict the composting dynamics including state variables, microbial activity, and matter conversion progress, dependent on conditions like raw material composition, thermal insulation, and aeration. Some simulations of composting processes are discussed, and working principles of special applications are explained. An experimental process is contrasted with its simulation to check how realistic the modelʹs assumptions are, and to discuss some fields of application of the model.