Improving Model-Based Systems Analysis of Waste Management
Model-based systems analysis is a tool to support decision-makers in the field of waste management. Of special concern in this thesis is the development of mathematical models for the analysis of the technological system. The aim of the models (here denoted WMS models) is to address whole waste management systems, i.e. from waste generation to final disposal including transports and possible means of recovery.
Many improvements have been made since the early WMS models in the mid-1960s. For example, the ability to take into account both environmental and economic parameters has widened the relevant information obtainable from the models. The general aim of this thesis is to evaluate and suggest how the model-based systems analysis of waste management can be further improved. Three problem areas are in focus:
The handling of surrounding technological systems (energy systems, waste management systems in other countries and material production systems)
The inclusion and analysis of waste prevention for Swedish conditions
The use of model-based systems analysis for waste management planning in Sweden
A conclusion from the research is that the increasing internationalization of waste management, especially in the European context, should be taken into account in further development and use of WMS models. For waste-to-energy technologies that can recover energy as district heat, this thesis shows that linking a WMS model to a district heating systems model improves the opportunity of finding an optimal solution for both systems and to more accurately handle the net electricity production and fuel replacements.
By using price elasticities to describe scrap markets, it was shown that the increased collection of scrap in a country can lead to a combination of increased recycling and decreased collection of scrap in other countries. So far, almost all WMS modelling have excluded a market effect and assumed that all collected scrap (minus material losses) will be used to replace virgin production. It was also shown that waste prevention clearly has a potential of leading to much larger reductions of greenhouse gas emissions in Sweden compared to material recycling or incineration.
It is suggested how the use of model-based systems analysis for waste management planning in Sweden could be increased through a close co-operation between consultant companies and organizations active in the field of waste management.
greenhouse gas emissions