Modeling and applying heuristics for optimization of solid waste collection under consideration of vehicle capacity

Abstract

The main contribution of this paper is to propose a general network flow optimization model for the problem of solid waste collection related to garbage management and transportation route planning. A model is formulated for a specific case in a big city in Vietnam. With the continuous increase of urban population in big cities of a developing country and the arising problem of waste management over the years, attempts have been made to organize the process of collecting solid waste from households and a series of tasks to ensure the best logistical steps. Considering the network of depots and information about the vehicles, we propose to apply heuristic algorithms from Operations Research to optimize the routes for vehicles to travel to depots and back. The research question thus concentrates on sequencing and routing with similar solution concepts as a classical Traveling Salesman Problem. For generating solution and implementation, we apply Evolutionary Algorithm using a commercial Solver tool. In general, network problem include cost of moving materials through a network involving varying demands, parameters, and constraints depending on the locations that the materials are being brought to. Problems of these type are characterized network flow optimization. The consideration of the connections between different parts of the network with inputs and outputs is what makes these problems difficult, but on the other side quite practical and applicable. The visual effect of a network flow model makes it useful for planning activities on the management level. Using numerical examples, we show that the efficiency of the evolutionary algorithm in the defined problem instances is better than any greedy approach. Finally, we discuss the similarity between the proposed model for solid waste collection and the problem of routing order pickers in multiple block warehouses.