Location of mixed municipal waste treatment facilities: Cost of reducing greenhouse gas emissions

Municipal solid waste treatment leads to the production of a considerable amount of mixed municipal waste, in case of which material recovery is difficult. Its treatment represents a worldwide challenge since landfilling is still a major treatment method and the respective emissions of greenhouse gases are significant. Approximately 126 Mt of municipal solid waste were landfilled or incinerated within the EU-28 in 2017, while the waste management sector produced 3% of the overall greenhouse gases emissions. Regarding mixed municipal waste, Waste-to-Energy plants seem to be a suitable disposal option as they substitute both landfills and energy production from fossil fuels in combined heat and power plants. However, new treatment facilities of this type need to take into account also the heat and electricity demands in their vicinity to ensure economic stability. This paper therefore analyses the relationship between greenhouse gases emissions and the cost of mixed municipal waste treatment, while considering environmental impact of different treatment options. A reverse logistic (mixed integer programming) model has been developed to optimise future strategies of mixed municipal waste treatment in a large geographical area. The model is nonlinear because of the nonlinear nature of the cost of mixed municipal waste treatment as well as the economic incentive associated with the avoided greenhouse gases emissions. These, in turn, are influenced by plant capacities, locations, and other location-specific parameters (such as the yearly heat demand profile) that must be considered during the integration of a future plant into the existing district heating systems. The results are presented through a case study for the Czech Republic, with 206 micro-regions (waste producers), 148 landfills, 113 potential mechanical-biological treatment plants, 24 potential locations for plants utilising refuse-derived fuels, 4 existing Waste-to-Energy plants, and 32 candidate locations for new Waste-to-Energy plants have been considered. The proposed future concepts involving various processing chains (small Waste-to-Energy plant, large Waste-to-Energy plant with the necessary complex logistics, mechanical biological treatment prior to incineration), are compared with the current (2016) waste treatment strategy, in which 73% of mixed municipal waste is landfllled. The trade-off between economically viable and environmentally acceptable solution is also targeted. The obtained data suggest a possible reduction in greenhouse gases emissions by almost 150% with the cost of waste treatment being increased only by approx. 2.5 EUR/t. (C) 2019 Elsevier Ltd. All rights reserved.