Economic and environmental comparison between two scenarios of waste management: MBT vs thermal treatment

Abstract

The paper examines, under specific local situation of planning of innovative solutions for municipal solid waste treatment, the results obtained from a technical, economic and environmental comparison between two different scenarios for waste management: the first scenario foresees the gasification of the residual waste after separate collection and the energetic utilization of the produced syngas, while the second one is based on a mechanical separation of the residual waste in three fluxes: a combustible flux to be utilized, after quality improvement, as RDF (residue derived fuel), a wet organic flux to be sent to anaerobic digestion and a residual essentially mineral flux. For both the scenarios different levels of separate collection were considered.The comparison took into account environmental and economic aspects.From the environmental point of view, the tool of LCA (life cycle assessment) has been used to address some key environmental aspects and the global acceptance of the two scenarios. As concerns the economic point of view, conventional economic criteria, i.e. investment and operating costs transferred to citizens, have been considered.For the practical implementation of the scenarios and in order to verify the possibility to adopt them in a specific territorial situation, additional aspects of practical management, reliability and need to individuate synergies with other territorial infrastructures have been considered.The results of the analysis for this specific case revealed that the MBT (mechanical biological treatment) option is preferable from the environmental point of view, while the pyro-gasification option is better from the economic point of view under the vast majority of operating conditions considered. Different practical implementations problems characterize both the scenarios.More generally, the comparison methodology that has been defined and used for the scenarios of the considered case can establish a more general useful approach, in order to help the definition of the best solution for waste management planning.