Estimation of municipal solid waste energy recovery potential using mathematical models of anaerobic biodigestion and incineration

Currently, one of the major problems faced by managers of solid urban waste is the final disposal of the waste generated by their population. Waste disposals should be done in spaces and/or under appropriate conditions, in order to minimize socioeconomic and environmental impacts. In this context, this article aims at estimating the energy recovery potential of urban solid waste using mathematical simulation models for anaerobic biodigestion and incineration. As object of study, the waste disposed in Caieiras landfill, located in the city of Caieiras/SP, was considered. To evaluate the anaerobic digestion, mathematical models were used to estimate methane production as function of the various factors that influence the process (acetate and microorganisms concentration, pH variation among others). In the case of incineration, empirical mathematical models (based on immediate, gravimetric and elementary analysis) were used to estimate the lower heating value of urban solid waste. According to the results obtained, it would be possible to obtain an average power of 38.8 MW for anaerobic digestion. If the incineration method was adopted, it would be possible to obtain an average electrical power of 214 MW (considering the total incineration of the waste). Based on the simulations carried out for anaerobic biodigestion and incineration as possible methods of municipal solid waste disposal, it is concluded that the incineration process of municipal solid waste presents a greater potential of electricity generation, approximately five times higher than the energy conversion potential of anaerobic digestion.