Mechanical biological treatment or selective collection for refuse derived fuel production?

The amount of municipal and industrial waste, produced in the European and not EU countries has grown strongly in the last decades. The characterization of municipal solid waste, together with their treatment, represents an important instrument for local governments and sanitation operators in achieving targets for waste recycling and recovery by the year 2020, in order to achieve EU legislation requests. In this article the authors analyze the production of Solid Recovered Fuel from a hypothetical case: MSW with a reference composition and applying different scenarios of selective collection, taking into account the mechanical biological treatment (MBT) bio-drying and/or bio-stabilization processes and the selective collection itself as “treatment” options. Results demonstrate that, in case of low efficiency of selective collection, the bio-drying process is an interesting opportunity to increase the amount of materials sent to recycling, to decrease the volumes of landfills for the management of MSW and finally to support the waste to energy sector through SRF production. The alternative process based on a preliminary screening and on the bio-stabilization of the undersieve has the problem of finding a sustainable pathway for the generated stabilized organic fraction. Bothe the approaches can modify the LHV of the waste to be sent to energy recovery. In extreme cases they can increase LHV from a value unfavorable for direct combustion to a value suitable for it. However that is not an energy generation as the treatment gives a concentration of the initially available energy in a lower mass. The case of high efficiency of selective collection is interesting for the potential indirect “generation” of a residual MSW similar to SRF (of course if the characterizing parameters are guaranteed steady through a specific treatment (no longer biological). In this case selective collection acts as a pre-treatment of MSW.