Optimisation of Solid Waste Collection Routes in Owerri Municipal Council Using Vehicle Routing Models

Municipal solid waste management in Owerri, the capital of Imo State in South East Nigeria, is characterised by incomplete collection coverage, prolonged evacuation intervals, and high operational costs driven by inefficient vehicle routing practices. This study applies the capacitated vehicle routing problem formulation to optimise the daily waste collection routes for the Imo Waste Management Agency's fleet of eight collection trucks serving the Owerri Municipal Council. A road network map of 94 collection points is digitised and attributed with estimated daily waste generation volumes from a physical characterisation survey. Vehicle capacity, working hours, and depot location constraints are encoded in the optimisation model. The nearest-neighbour heuristic generates an initial solution, which is subsequently improved using a 2-opt local search procedure. The optimised routing plan reduces total daily vehicle travel distance by 24 percent from 387 kilometres to 294 kilometres, enabling the same fleet to cover 14 additional collection points per day. Fleet fuel cost savings are estimated at 2.1 million naira per month under current diesel prices. Coverage analysis demonstrates that the optimised routes achieve 97 percent of collection points within the target 72-hour evacuation interval, compared to 84 percent under current practice. The study provides an operations research-based framework for sustainable municipal solid waste logistics planning. Keywords: vehicle routing, solid waste management, Owerri, capacitated VRP, route optimisation.