Optimizing the treatment and disposal of municipal solid wastes using mathematical programming—A case study in a Greek region

• Non-linear mathematical programming was adopted to optimize a MSW system.
• We optimally allocated eight MSW components to four treatment techniques.
• Total cost and total equivalent CO2 emissions were minimized.
• The methodology was applied to the Region of East-Macedonia and Thrace in Greece.
• The optimal fates of the MSW components varied according to the objective function.

Goal of the work is to present a simplified methodology to optimize an integrated solid waste management system. The methodology performs two optimizations, namely: (i) minimization of the total cost of the MSW system and (ii) minimization of the equivalent carbon dioxide emissions (CO2e) generated by the whole system. The methodology is modeled via non-linear mathematical equations, uses 32 decision variables and does not require complex LCA databases. The proposed model optimally allocates eight MSW components (paper, cardboard, plastics, metals, glass, food wastes, yard wastes and other wastes) to four MSW management technologies (incineration, composting, anaerobic digestion, and landfilling) after source separation of recyclables has taken place. The Region of East-Macedonia and Thrace in Greece was selected as a case study. Results showed that there is a trade off between cost and CO2e emissions. Incineration and composting were favored as the principal treatment technologies, while landfilling was always the least desirable management technology under both objective functions. The recycling participation rate significantly affected all optimum scenarios.