Landfilling is an unavoidable component of a municipal waste management system; being the least sustainable option, it is on the other hand essential to manage waste materials that cannot be recycled or recovered in other ways. Various technologies have been studied to minimize the impacts deriving from landfills, which today are complex engineering works. The semi aerobic landfill method has been developed in Japan a few decades ago; its configuration alternates aerobic and anaerobic zones that allow to accelerate the waste stabilization, reducing the aftercare period and costs. It can be considered a compromise between an aerobic and anaerobic landfill. Life cycle assessment (LCA) is a widespread methodology used to assess the environmental impacts of a product or system throughout its entire lifetime. This approach is adopted in many sectors and also finds application in the waste management system, where it is useful for evaluating the environmental performance of either the system as a whole or the individual technologies involved. Some LCA studies have been performed on traditional landfills, but semi aerobic landfills are rarely modelled in detail. To overcome the lack of assessments on this topic in the literature, Lazzarin (2015/2016) and Sciarrone (2020/2021) analysed through a LCA study the environmental impact of a semi aerobic landfill located in northern Italy. The aforementioned studies, in accordance with most scientific literature cases, highlighted the strong contribution of leachate on the total impact of a landfill and the consequent importance of its appropriate treatment. This project introduces the construction and operation of a leachate treatment plant as an integral part of the life cycle of a landfill, and considers a purified leachate of optimal quality, well below the legal concentration limits. The goal of the present study is to evaluate the environmental impact of the leachate treatment plant used to treat the leachate produced over the entire life of a semi aerobic landfill; moreover, the role of leachate treatment in improving the environmental performance of the landfill will be discussed. The LCA is conducted in compliance with the ISO 14040 and 14044 standards using the SimaPro software and the impact assessment is performed using the ReCiPe 2016 assessment method. The functional unit is defined as “landfilling of 1 ton of wet unsorted waste in a landfill with an average depth of 10 meters for 100 years”. The system boundaries of the model include the entire life of the leachate treatment plant which is divided into 5 phases: plant construction and plant operation during the different life stages of the landfill (i.e. operation, aftercare, closure, conversion). In the operational phase, the treatment plant consists of a combination of reverse osmosis, solar evaporation, phytoremediation and adsorption; while starting from the aftercare phase, thanks to the better quality of the leachate produced, only phytoremediation and adsorption are performed. Each leachate treatment unit consists of a set of construction/management processes and receives as inputs the materials, natural resources and energy necessary to complete each activity involved. Similarly, outputs in terms of waste by-products such as exhausted membranes, solid salts, biowaste and spent activated carbon are also produced. The data for the assessment are taken from the preliminary design of the leachate treatment plant, market suppliers’ data, ecoinvent database and literature. The results are then compared with similar cases in the literature to highlight similarities and differences. In the literature there is a lack of LCA studies that consider the leachate treatment plant as part of the landfill system, therefore the results obtained provide a baseline scenario from which future studies can start to assess the impacts of leachate management by modelling more complex systems.
Il conferimento in discarica è una componente imprescindibile di un sistema di gestione dei rifiuti urbani. Diverse tecnologie sono state studiate per ridurre al minimo gli impatti derivanti dalle discariche, che oggi sono complesse opere di ingegneria. Il metodo di discarica semi aerobico è stato sviluppato in Giappone alcuni decenni fa e consente di accelerare la stabilizzazione dei rifiuti. L’analisi del ciclo di vita (LCA) è una metodologia diffusa utilizzata per valutare gli impatti ambientali di un prodotto o sistema durante l'intero ciclo di vita. Questo approccio è adottato in molti settori e trova applicazione anche nel sistema di gestione dei rifiuti, dove è utile per valutare le prestazioni ambientali sia dell'intero sistema che delle singole tecnologie coinvolte. Alcuni studi LCA sono stati eseguiti su discariche tradizionali, ma le discariche semi aerobiche sono raramente modellate in dettaglio. Per sopperire alla mancanza di valutazioni su questo argomento in letteratura, Lazzarin (2015/2016) e Sciarrone (2020/2021) hanno analizzato attraverso uno studio LCA l'impatto ambientale di una discarica semi aerobica situata nel nord Italia. I suddetti studi, in accordo con la maggior parte dei casi della letteratura scientifica, hanno evidenziato il forte contributo del percolato sull'impatto totale di una discarica e la conseguente importanza di un suo trattamento appropriato. Questo progetto introduce la costruzione e l'esercizio di un impianto di trattamento del percolato come parte integrante del ciclo di vita di una discarica, e considera un percolato purificato di qualità ottimale, ben al di sotto dei limiti di concentrazione di legge. L'obiettivo del presente studio è valutare l'impatto ambientale dell'impianto di trattamento del percolato utilizzato per trattare il percolato prodotto durante l'intera vita di una discarica semi aerobica; verrà inoltre discusso il ruolo del trattamento del percolato nel miglioramento delle prestazioni ambientali della discarica. La LCA è stata condotta in conformità alle norme ISO 14040 e 14044 utilizzando il software SimaPro e la valutazione di impatto è stata eseguita utilizzando il metodo di valutazione ReCiPe 2016. L'unità funzionale è definita come “smaltimento di 1 tonnellata di rifiuti umidi indifferenziati in una discarica con una profondità media di 10 metri per 100 anni”. I confini di sistema del modello comprendono l'intera vita dell'impianto di trattamento del percolato, che si articola in 5 fasi: costruzione dell'impianto e funzionamento dell'impianto durante le diverse fasi di vita della discarica (esercizio, post-trattamento, chiusura, riconversione). L'impianto di trattamento, nella fase di esercizio della discarica, consiste in una combinazione di osmosi inversa, evaporazione solare, fitodepurazione e adsorbimento; mentre a partire dalla fase di post-trattamento, grazie alla migliore qualità del percolato prodotto, si eseguono solo fitodepurazione e adsorbimento. Ciascuna unità di trattamento del percolato è costituita da un insieme di processi di costruzione/gestione e riceve come input i materiali, le risorse naturali e l'energia necessarie per completare ogni attività coinvolta. Allo stesso modo, vengono prodotti anche gli output in termini di sottoprodotti di scarto come membrane esauste, sali, rifiuti organici e carbone attivo esaurito. I dati per la valutazione sono tratti dalla progettazione preliminare dell'impianto di trattamento del percolato, dai dati dei fornitori di mercato, da ecoinvent e da letteratura. I risultati ottenuti forniscono uno scenario di base dal quale potranno partire studi futuri per valutare gli impatti della gestione del percolato modellando sistemi più complessi.
Valutazione d'impatto ambientale del trattamento del percolato in discarica semi-aerobica attraverso la valutazione del ciclo di vita.
ZAMAR, GIULIA
2021/2022
Abstract
Landfilling is an unavoidable component of a municipal waste management system; being the least sustainable option, it is on the other hand essential to manage waste materials that cannot be recycled or recovered in other ways. Various technologies have been studied to minimize the impacts deriving from landfills, which today are complex engineering works. The semi aerobic landfill method has been developed in Japan a few decades ago; its configuration alternates aerobic and anaerobic zones that allow to accelerate the waste stabilization, reducing the aftercare period and costs. It can be considered a compromise between an aerobic and anaerobic landfill. Life cycle assessment (LCA) is a widespread methodology used to assess the environmental impacts of a product or system throughout its entire lifetime. This approach is adopted in many sectors and also finds application in the waste management system, where it is useful for evaluating the environmental performance of either the system as a whole or the individual technologies involved. Some LCA studies have been performed on traditional landfills, but semi aerobic landfills are rarely modelled in detail. To overcome the lack of assessments on this topic in the literature, Lazzarin (2015/2016) and Sciarrone (2020/2021) analysed through a LCA study the environmental impact of a semi aerobic landfill located in northern Italy. The aforementioned studies, in accordance with most scientific literature cases, highlighted the strong contribution of leachate on the total impact of a landfill and the consequent importance of its appropriate treatment. This project introduces the construction and operation of a leachate treatment plant as an integral part of the life cycle of a landfill, and considers a purified leachate of optimal quality, well below the legal concentration limits. The goal of the present study is to evaluate the environmental impact of the leachate treatment plant used to treat the leachate produced over the entire life of a semi aerobic landfill; moreover, the role of leachate treatment in improving the environmental performance of the landfill will be discussed. The LCA is conducted in compliance with the ISO 14040 and 14044 standards using the SimaPro software and the impact assessment is performed using the ReCiPe 2016 assessment method. The functional unit is defined as “landfilling of 1 ton of wet unsorted waste in a landfill with an average depth of 10 meters for 100 years”. The system boundaries of the model include the entire life of the leachate treatment plant which is divided into 5 phases: plant construction and plant operation during the different life stages of the landfill (i.e. operation, aftercare, closure, conversion). In the operational phase, the treatment plant consists of a combination of reverse osmosis, solar evaporation, phytoremediation and adsorption; while starting from the aftercare phase, thanks to the better quality of the leachate produced, only phytoremediation and adsorption are performed. Each leachate treatment unit consists of a set of construction/management processes and receives as inputs the materials, natural resources and energy necessary to complete each activity involved. Similarly, outputs in terms of waste by-products such as exhausted membranes, solid salts, biowaste and spent activated carbon are also produced. The data for the assessment are taken from the preliminary design of the leachate treatment plant, market suppliers’ data, ecoinvent database and literature. The results are then compared with similar cases in the literature to highlight similarities and differences. In the literature there is a lack of LCA studies that consider the leachate treatment plant as part of the landfill system, therefore the results obtained provide a baseline scenario from which future studies can start to assess the impacts of leachate management by modelling more complex systems.| File | Dimensione | Formato | |
|---|---|---|---|
|
Zamar_Giulia.pdf
accesso aperto
Dimensione
10.38 MB
Formato
Adobe PDF
|
10.38 MB | Adobe PDF | Visualizza/Apri |
The text of this website © Università degli studi di Padova. Full Text are published under a non-exclusive license. Metadata are under a CC0 License
https://hdl.handle.net/20.500.12608/9995