Parameter interrelationships in a dual phase GIS-based municipal solid waste collection model.

Geographic information systems are a valuable tool for waste collection and optimization, but they have been underutilized in helping to understand the complex interrelationships that exist within a dual phase solid waste collection system. A GIS-based dual phase model integrating the handcart pre-collection phase and truck collection phase for a study area located in Hai Phong, Vietnam was proposed, and a resulting total system cost was estimated. Temporary collection points were first identified using both the maximize coverage and minimize facility location-allocation tools from a list of candidate temporary collection points and constraints. Two vehicle routing problems were then separately modeled for handcart and truck routes. A total of 30 scenarios were considered in order to investigate the interrelationships between the model parameters, with respect to the total operation costs and maintenance system costs. The scenario with 11 temporary collection points and a maximum handcart collection distance of 500 m gave the lowest overall cost in the study area. The results suggest a single temporary collection point in the study is able to serve about 2,590 people in an area of 0.11 km2. Compared to the status quo condition, a 13.76% reduction in truck travel distances is attainable using the proposed model. It is found that the number and distribution of temporary collection points greatly affected the cost effectiveness in both pre-collection and collection phases.