## 2 A Case Study for the MSW Management of the Procida Island  
### The System under Analysis and the Functional Unit  
The study utilised an attributional, process-based approach, meaning that it accounted for impacts that directly relate to the system under analysis and to its activities. The standard guidelines of ISO 14044 [6] were used as a main reference. The stage of \"Goal and Scope Definition\" identified the \"_system to be studied_\" as the management scheme of the Procida municipality, starting from waste separate collection through to the recovery of secondary resources and the disposal of residues. The \"_function of the systems under analysis_\" was the management of solid waste generated in Procida in 2011 and 2021 (Figure 2) and gathered by a separate collection system. The focus was on the main waste streams, those concerning the organic fraction (namely, biowaste), dry recyclables (paper, plastics, metals, and glass), and unsorted residual waste (URW, to be sent for thermal treatment or landfilling). This excluded some minor waste streams (less than 10% of MSW, as shown in ANNEX A), such as bulky waste, WEEE, and textiles, the management of which is determined according to national criteria and is not affected by the performances of a local management scheme. The aim was to investigate the potential improvement achieved by the waste management scheme adopted over the last 10 years, with particular attention to end-of-life packaging of interest for Conai. The \"_functional unit_\" was the treatment of one tonne of MSW collected in Procida, following the suggestion of [5], with the aim of monitoring management and technology improvements, without the possible effects of different waste-generation rates. Figure 2: _Cont._  
The reference composition as obtained is reported in Figure 3, starting from the compositions of all the separately collected waste streams (as available on W-MySir) and that of URW (obtained by combining the composition of URW in input to the waste-to-energy (WtE) unit active in Campania [3], coupled with the separation efficiencies of the material recovery facility, MRF, active in the same regional area [8]). Most of data were acquired by the W-MySir platform, with the support of Conai, who provided data related to the selection and remanufacturing residues of the main recycling chains, indicating that the _\"quality of data\"_ was quite high. Moreover, an extended analysis of scientific and technical studies was carried out to estimate and compare all the direct and avoided environmental burdens. The Ecoinvent databank v.3.6 [9] was used to quantify the indirect burdens, while those related to the infrastructures were not considered. Figure 3: Reference composition for the functional unit of the study. Adapted from: W-MySir [7]. Figure 2: Quantified flow sheet of MSW management in Procida in 2011 (**top**) and 2021 (**bottom**), with reference to functional unit. Data are expressed in kg. EWC: European waste code; I: import; E: export. Data Source: W-MySir [7]. The system expansion methodology (also known as the \"avoided burdens method\") was used to solve the \"_allocation problem_\". In other words, as performed in previous studies [10], the products that were replaced on the markets by the obtained co-products (e.g., recycled plastics, metals, glass, and paper, as well as recovered energy) were identified and their substitution was included in the model. The study evaluated the substitution potential \(\gamma\) of an available market product with a recovered resource as the product of four parameters: \(\gamma=U\cdot\eta\cdot\alpha\cdot\pi\), as recommended by [PERSON] et al. [11].