SCHEDULING OF SOLID WASTE COLLECTION ROUTES

Abstract

Routing of solid waste collection vehicles in Nigeria poses a challenging task because of attitudinal and haphazard infrastructure problems to contend with. The objective is to minimize the overall cost, which was essentially based on the distance travelled by collection vehicles. The study proposes heuristic methods to generate feasible solution to an extended capacitated Chinese Postman Problem (CCPP) in undirected network. The heuristic procedure consist of “route first, cluster second” and “cluster first, route second” and was applied to scheduling solid waste collection problems in two cities – Abuja and Onitsha. The two techniques were compared and with the existing schedule with respect to cost, efficiency, and distance travelled. A cost model was developed to compare the quality of solution derived. The adoption of the proposed heuristics in Onitsha resulted in reduction of the number of existing vehicles by three, $325.90 (or 7.65%) in refuse collection cost and 28.17km (or 6.03%) in vehicle distance travelled per day. In Abuja, the heuristics produced routes which could save about 19.08km travel per day and $31.10 (or 21.09%) of collection cost per day. Efficiency in refuse collection was increased from 86% to 98% in Abuja and 75% to 95% in Onitsha. The results revealed a good performance of the proposed heuristic methods which will find useful applications in other areas of vehicle scheduling.