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

The paper examines, under specific local situation of planning of innovative solutions for municipalsolid waste treatment, the results obtained from a technical, economic and environmental comparisonbetween two different scenarios for waste management: the first scenario foresees the gasification ofthe residual waste after separate collection and the energetic utilization of the produced syngas, whilethe second one is based on a mechanical separation of the residual waste in three fluxes: a combustibleflux to be utilized, after quality improvement, as RDF (residue derived fuel), a wet organic flux to be sentto anaerobic digestion and a residual essentially mineral flux. For both the scenarios different levels ofseparate 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 addresssome key environmental aspects and the global acceptance of the two scenarios. As concerns the eco-nomic point of view, conventional economic criteria, i.e. investment and operating costs transferred tocitizens, have been considered.For the practical implementation of the scenarios and in order to verify the possibility to adopt themin a specific territorial situation, additional aspects of practical management, reliability and need toindividuate 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 betterfrom the economic point of view under the vast majority of operating conditions considered. Differentpractical implementations problems characterize both the scenarios.More generally, the comparison methodology that has been defined and used for the scenarios of theconsidered case can establish a more general useful approach, in order to help the definition of the bestsolution for waste management planning.