Gauging HWRC performance from vehicle weigh-ticket data

Abstract

This paper describes a modelling approach designed to investigate the variability in nett amenity bin weights produced by nine household waste recycling centres (HWRCs) in West Sussex, UK over a 12-month period. Compaction technique, vehicle type, site design and month were identified as key factors explaining 76% of the variability in the data. For each significant factor, a weighting coefficient was calculated to generate a predicted nett weight for every bin transaction. Analysis of predicted and observed mean bin weights suggested that three sites had similar characteristics but returned significantly different mean nett bin weights. Subsequent waste and site audits determined the possible sources of the remaining variability. Significant differences were identified in the proportions of bagged waste and dry recyclables deposited in the amenity waste stream at the sites, with significantly less observed at one site. Operational and managerial techniques (e.g. material separation, compaction frequency and site management ethos) were also identified as factors impacting on mean bin weights and general site performance. The model can be used to identify sites producing significantly different bin weights, enabling detailed ‘back-end’ waste analyses to be efficiently targeted and best practice in HWRC operation identified.