Optimal Management Methodology for Solid Wastes in Urban Areas

Solid waste management (SWM) is one of the priority issues concerning the protection of the environment and conservation of natural resources. It is imperative for environmental managers and planners to follow a sustainable approach to municipal solid waste (MSW) management and to integrate strategies that will produce the best practicable option. Solid waste management is among the basic essential services provided by municipal authorities in the country to keep urban areas clean. The methodology presented in this work is based on optimization formulation in which the overall objective is the minimization of daily waste-management costs and their components. The cost includes the investment, waste handling expenses, transportation costs, expenses owing to the use of replacement trucks, and the income from waste products, such as refuse-derived fuel (RDF) and energy. The constraints include those linking waste flow among sources, plants and landfills, capacity, site selection, facility availability, environmental, and landfill saturation. The integer and mixed-integer mathematical formulation of the solid waste optimization model was solved by using commercially available optimization software, Lingo 10.0. Different scenarios were constituted to demonstrate the potential applicability of the model. The sensitivity analysis indicated that the total cost lowered with the high quality of incinerators (with lesser unrecovered wastes). Sensitivity analysis of different landfill sites reveals their suitability for different planning horizons. The mixed-integer optimization model consistently performed better than the integer model.