VALUTAZIONE DEI FLUSSI DI SCARTO NELLA GESTIONE DEI RIFIUTI URBANI IN ITALIA

An effective separate collection of municipal waste is a necessary condition for a high-quality recycling system, with the aim of preserving natural resources and reducing impacts on environment. The quantification of residual municipal waste is essential for the proper planning of an effective management system, in particular for the definition of the treatment capacity needed in a region or a country. The municipal waste not suitable for material recovery is composed by the unsorted municipal waste and by the residual waste flows from the treatment of municipal waste collected separately. While the first is effectively monitored and easily quantifiable, the second one must be estimated and varies with the separate collection rate and its quality. Residual waste must be managed considering the potential environmental impacts and preferring incineration with energy recovery to landfill disposal; in Italy in 2018, 22% of municipal urban waste was disposed in landfill. The aim of this study is the assessment of residual waste flows from material recovery operations of municipal waste from separate collection. The analysis was focused on the main fractions (organic fraction, paper and carboard, plastics, glass, wood, metals) that are representative for the 88% of the municipal waste collected separately. The material recovery operations were divided in three main stages: separation of different fractions collected on a multi-material basis, selection of each fraction in order to remove inappropriate materials from the recoverable ones, recycling processes. In each treatment stage, a flow of mixed waste is generated; it can’t be sent to material recovery and it is sent to alternative treatments based on its composition. As far as possible, public data representative of the national average were used. When the amount of residues was not declared, it has been assessed considering treatment efficiencies or the amount of avoided use of raw materials from natural resources. In order to include in the analysis all the municipal waste collected and not only the main fractions (on which this analysis was focused), the other minor fractions of separate collection (for example household construction and demolition waste, household bulky waste) were assessed, assuming that the treatment residues suitable for energy recovery account for the 10% of the total waste flow. The analysis considered the Italian municipal waste production in 2018 (30,2 million tons) when the average separate collection rate was 58%. The results show that the treatment of waste collected separately generates 3,4 million tons of mixed waste: 3 million are suitable for incineration with energy recovery. These residues account for 20% of total waste from separate collection; they increase the amount of residual municipal waste (that per se represents the 42% of total municipal waste production) by 27%; the municipal waste not suitable for material recovery managed in 2018 was 16,1 million tons; 15,7 million tons were suitable for incineration with energy recovery.

Una buona raccolta differenziata è la prima condizione per sostenere una filiera di riciclo di alta qualità, con il fine ultimo della preservazione delle risorse naturali e la riduzione degli impatti sull’ambiente. Per una corretta pianificazione della gestione dei rifiuti urbani non destinabili a recupero di materia e una valutazione dei fabbisogni impiantistici, occorre conoscere non solo la produzione di rifiuto urbano residuo, ma anche quantificare i flussi di scarto derivanti dai trattamenti delle raccolte differenziate. Questi rifiuti devono essere gestiti con particolare attenzione al contenimento degli impatti ambientali e quindi preferendo l’incenerimento con recupero di energia allo smaltimento in discarica, al quale nel 2018 in Italia si è ancora fatto ricorso per la gestione del 22% dei rifiuti urbani. La quantificazione degli scarti generati nelle operazioni di recupero delle frazioni differenziate è stata l’obiettivo di questo lavoro. Dall’analisi è emerso che, a fronte di una produzione nazionale di rifiuti nel 2018 pari a 30,2 milioni di tonnellate e una raccolta differenziata del 58%, l’attuale gestione e trattamento dei rifiuti raccolti in modo differenziato generano circa 3,4 milioni di tonnellate di scarti, di cui 3 milioni sono idonei al recupero energetico. Il totale degli scarti costituisce circa il 20% del materiale raccolto per via differenziata; se sommati al rifiuto urbano residuo attualmente generato, lo incrementano del 27% portando il quantitativo complessivo a 16,1 milioni di tonnellate all’anno, di cui 15,7 possono essere avviate a recupero energetico.