A review on mathematical modeling of in-vessel composting process and energy balance

Composting is an integral part of waste management. In-vessel composting makes for a more efficient compost within a short period. Composting allows the transformation of waste into a useful product. However, the processes involved and the end product can differ concerning quality, performance, or safety. Composting, an exothermic process, is majorly regulated by temperature monitoring. Models have been established to represent some features of the composting process, but never all of them together. In general, the energy balance is defined by the decomposition degree and the heat removal associated with it. Temperature is a vital modeling state variable which could be simulated at any moment by estimating the change in heat balance components. This article explores the composting mechanism mathematical models and heat balance, and evaluates their efficiency. Composting process mathematical models were developed from both mass balance and energy perceptions, with approaches generally established over time, and sometimes spatially. To summarize the work conducted on in-vessel composting mathematical modeling and energy balance, the authors performed a systematic review of literature citing research and review articles in peer-reviewed journals and theses. This review covers 60 scientific research articles from 2005 to 2019. The data gathered is useful in the control, design, and management of the composting operations as well as in improving the performance and productivity of the bioreactors.