Circular Economy in Waste Management: Network Flow Problem and Recycling Dilemma

abstract

en

Recent research on waste management has primarily focused on the circular economy. This concept leads to increasing sustainability by putting emphasis mainly on the reduction of waste production, recycling, and restriction of landfilling. For the European Union, it is anchored in Circular Economy Package by separation and recycling goals. The obligation of member states is to put these goals into local legislation, while its effective implementation can be aided by mathematical programming. The article mainly focuses on the effectivity of sorting waste in sorting lines, which must be done before the following manufacturing of waste into secondary material. The general public awareness about the sorted waste is that all material can be recovered. However, real operations confirm that the return flow of non-recyclable or hardlyrecyclable material increases as the maximum recycling rate is achieved. The goal is to determine dependency of the recycling process on the separation rate, which represents how much citizens sort their waste. The dependencies are studied for the main sorting fractions of municipal solid waste – plastic and paper. Afterwards, the influence of these dependencies is studied in the case study of waste management in the Czech Republic by sophisticated approach concerning economic and environmental impact. The task represents a network flow model, where several commodities of the produced waste are transported between producers and treatment facilities. The optimisation considers minimising trade-off between the mentioned criteria. Economic criterion is included through cost related to waste collection, its transport, sorting and final treatment. Environmental impact is measured by greenhouse gases produced, which is being expressed by the CO2eq unit. It is an equivalent for carbon dioxide that is based on the global warming potential ofvarious greenhouse gases. The model formulated as mixed integer programming problem is implemented in the GAMS (General Algebraic Modeling System). Estimated real nonlinear dependencies describing separation and recycling efficiencies are used in the task. The results are discussed, and some solutions are suggested for future research.

Recent research on waste management has primarily focused on the circular economy. This concept leads to increasing sustainability by putting emphasis mainly on the reduction of waste production, recycling, and restriction of landfilling. For the European Union, it is anchored in Circular Economy Package by separation and recycling goals. The obligation of member states is to put these goals into local legislation, while its effective implementation can be aided by mathematical programming. The article mainly focuses on the effectivity of sorting waste in sorting lines, which must be done before the following manufacturing of waste into secondary material. The general public awareness about the sorted waste is that all material can be recovered. However, real operations confirm that the return flow of non-recyclable or hardlyrecyclable material increases as the maximum recycling rate is achieved. The goal is to determine dependency of the recycling process on the separation rate, which represents how much citizens sort their waste. The dependencies are studied for the main sorting fractions of municipal solid waste – plastic and paper. Afterwards, the influence of these dependencies is studied in the case study of waste management in the Czech Republic by sophisticated approach concerning economic and environmental impact. The task represents a network flow model, where several commodities of the produced waste are transported between producers and treatment facilities. The optimisation considers minimising trade-off between the mentioned criteria. Economic criterion is included through cost related to waste collection, its transport, sorting and final treatment. Environmental impact is measured by greenhouse gases produced, which is being expressed by the CO2eq unit. It is an equivalent for carbon dioxide that is based on the global warming potential ofvarious greenhouse gases. The model formulated as mixed integer programming problem is implemented in the GAMS (General Algebraic Modeling System). Estimated real nonlinear dependencies describing separation and recycling efficiencies are used in the task. The results are discussed, and some solutions are suggested for future research.

Municipal Solid Waste; Network Flow Problem; Recycling Efficiency; Multi-Objective; Circular Economy

26.08.2020

2653-8911

7

1

20–20

1