Planning Source Separated Collection and Final Disposal of Municipal Solid Waste in Campania Region

The introduction of integrated systems far municipal solid waste (MSW) management has underlined the need far the simultaneous use of a variety of options in the collection, treatment and disposal of different waste components. In order to take into account the possible consequences that each option might have on the others in an integrated system, decisional mathematical models are employed so as to optimise the flows of solid waste collected in a number of different ways and diverted to treatment plants. The model is based on a representation of the integrated system as a network of nodes and lines, and is described using mass and energy balance. Waste flows along the lines are considered the unknowns of the model and are calculated by minimising total network management costs. Environmental, social and technical constraints are also included and the application of the model for solid waste flow optimisation in Campania Region (Italy) is presented. Following the indications of the regional programme, two territorial areas for municipal solid waste management are defined, and four different scenarios are investigated for each of them. Each scenario refers to a fixed objective of material recovery from source separated collection and corresponds to a successive phase of waste management programme application. Source separated collection of miscellaneous organic waste from specific producers and source separated collection of glass, metals, paper and plastic from domestic producers are considered, together with commingled solid waste collection from both specific and domestic producers. In compliance with the provisions of the regional programme, the following treatment facilities and final disposal sites are envisaged: composting plants located near the production centres for the treatment of source separated waste coming from specific producers; material recovery facilities for the treatment of commingled solid waste in order to produce RDF and stabilise the biodegradable organic fraction; incinerators with energy recovery capability, where RDF coming from material recovery facilities is burned; sanitary landfills for the final disposal of ashes produced by incineration plants and other residues. The preferred options for collection, treatment and disposal of each MSW component and the required capacities of treatment plants and disposal sites are derived. The results obtained show several differences between the two considered territorial areas, due to the differing MSW composition. In the first area, source separated collection turns out to be appropriate only for materials having a low specific energy content: the others are source separately collected only in order to reach the minimum assigned percentage of recovered materials far the considered scenario. In the second territorial area, the minimum percentage of recovered materials that can justify the cost of source separated collection is 38%: this percentage also includes a certain quantity of paper and plastics. The total energy recovered varies in the considered scenarios because of the fall in RDF production and its lower specific energy content. Similar results are also found far the production of ashes and residues. Finally a substantial reduction in the required capacity of treatment plants and disposal sites, especially far the first territorial area, is obtained by the successive application of the regional programme. The residual capacity can be then used for industrial waste.