Exergoeconomic analysis of a Mechanical Biological Treatment plant in an Integrated Solid Waste Management system including uncertainties

Abstract

Municipal Solid Waste disposal is still a crucial issue, which is influenced by heterogeneous factors (political, social, economic and technological). The Mechanical Biological Treatment (MBT) plant is an important element of an Integrated Solid Waste Management system. These plants are aimed at separating the light and dry fraction of the Unsorted Waste from the wet one, producing the Refused Derived Fuel and recovering the metal parts. In the present work, an Exergoeconomic analysis is performed on two MBT plant structures in order to assess the unit exergy-based cost of products and allocate the irreversibility associated to each equipment. A linear variation of degree of Selective Collection (SC) of single materials (±30% respect to the base case) shows that the major influence on production costs is associated to the SC of plastic. A Monte Carlo simulation is then carried out by sampling from distributions of external (waste composition) and internal (energy consumption) uncertain variables. The resulted mean values (μ) and standard deviations (RStD) can be useful at the time of designing a new plant. The influence of the internal variable is definitely lower than the external one, with values of RStD more than 90% lower.