Search

Browse

• Communities
• Authors
• Year
• Titles
• Subjects

My Space

• Login

Modelling solid waste management systems, using advanced life cycle assessment (LCA) tools

Chazirakis Panagiotis

Full record

---

Summary

The problems arising from environmental impacts associated with human activities have intensified in recent decades. Governments, particularly the European Union, have focused on creating, establishing, and implementing legal frameworks, directives, and guidelines. Their short-term goal is the minimization and, in the long term, the reversal of these negative environmental impacts. Directive 851/2018 (EU) introduces environmental protection and human health measures to manage urban solid waste. These measures aim to prevent or reduce waste production, mitigate the negative consequences of production and waste management, limit the overall impact of resource use, and enhance the waste management system efficiency. Simultaneously, the new climate law, Law No. 4936/2022, establishes measures and policies for the country's adaptation to climate change and ensures decarbonization by 2050. These initiatives play a crucial role in transitioning to a circular economy and ensuring the long-term competitiveness of the European Union. Therefore, exploring new waste management scenarios and modernizing existing systems must align with the new guidelines. Specifically, goals for reducing biowaste ending up in landfills and decreasing the consumption of natural resources necessitate revising and redesigning existing waste management systems. However, as the systems undergo modernization, the question arises about the environmental benefits of these upgrades and the tools that can evaluate this transition.The Life Cycle Assessment (LCA) in managing solid waste represents a precious tool for understanding environmental impacts and the in-depth exploration of the processes that regulate such a system. Through this methodology, management plans ranging from simple to highly complex can be examined and analyzed. Indeed, as the boundaries of the studied system expand and the system becomes more complex, taking into account more information and data, the need for computational power increases correspondingly. Therefore, using specialized computational tools becomes essential for achieving the goals of each research study.In this thesis, the integrated waste management system of the Chania region in Crete, which represents a typical Mediterranean integrated waste management system (IWMS), underwent a comprehensive study and modelling through extensive waste sampling and data collection. Such as weighting, truck travel logs, and fuel consumption info from the waste collection fleet were easily accessible to waste managers. The resulting data enabled an in-depth analysis of the critical processes involved in collecting, transporting, and treating municipal solid waste. This valuable information was utilized to enhance the understanding of the system's dynamics and environmental impacts.Additionally, the present thesis evaluated the environmental impact associated with existing waste collection practices in the Chania region of Greece. Herein, the introduction of waste transfer stations was considered in the context of resource consumption. The study leveraged actual, readily accessible data, such as weight records, total monthly fuel consumed, and total distance travelled by the collection vehicles, to create and evaluate a life cycle assessment inventory. Advanced LCA tools software was used to compare the implications of varying waste transfer station locations and quantities in a modern integrated solid waste management system. Using the produced data, five scenarios – one conventional direct haul and four scenarios including waste transfer stations - were explored, and their environmental impacts and efficiencies within the context of integrated waste management were assessed. The aim was to provide a comprehensive analysis that can inform better waste management practices, balancing operational efficiency, resource consumption, and environmental impact. The final results showed that a combination of direct and assigned to waste transfer stations (WTS) transport is the optimal scenario for the region but also revealed the benefits arising from proper and methodical transportation programming.Moreover, mechanical composting is a popular treatment method for the mechanically separated organic fraction of municipal solid wastes (MSW) to stabilize the waste material and reduce its environmental impacts. The model and life cycle inventory database were created based on the existing centralized mechanical composting facility in Chania (Crete, Greece). All stages of the composting process, wherein input-output flows were comprehensively analyzed based on specific waste fragments. The transfer coefficients were calculated for each waste fragment throughout the processes. The degradation rate was measured as kg of C and N released per mg of the treated material. The results show that process degradation rates are independent of the initial fragmental composition. This is the first study that accurately models the fate of specific waste fragments in a composting plant. At the same time, the developed life cycle inventory (concerning mass and energy balances) can be applied to estimate the environmental impacts regarding mechanical composting of the organic fraction of municipal solid wastes.Lastly, an LCA was performed to investigate the environmental impacts of two alternative approaches in a biowaste management system. The system inventory was based on actual data and on-site sampling for two consecutive years at the mechanical and biological treatment (MBT) facility in the prefecture of Chania (Greece). The facility pertains to MBT for household waste and material recycling facility (MRF) for the recyclable fractions in two different process lines. The mass balances and environmental performance were assessed from waste generation to end-use. The LCA and ReCiPe 2016 methodology allowed for estimating the endpoint environmental impacts on human health, ecosystem quality and resource scarcity. The results show that biowaste source segregation in an integrated waste management system significantly benefits its recoverability potential and environmental performance. Impacts on human health (HH) have been reduced by 4.6 times, on freshwater ecosystem quality (EQf) by 6.3 times, and resource scarcity (RS) usage by 2.5 times when biowaste is combined with compost production and use, material recovery and reprocessing for fertilizer and raw material substitution.

Available Files

Services