Modeling Spatial Variation in the Demand for Waste Collection Service

Abstract

Three models were developed for spatially projecting the demand for waste collection service by manufacturing, retail, and service businesses, and were compared with a model commonly used for this purpose. Model I is similar to most earlier work in which unit demand rates (kg employee^-1 wk^-1) are estimated for a variety of businesses. These rates are then multiplied by the number of employees in the area being modeled. Model II differs from Model I in that unit demand rates are estimated for businesses of different sizes (number of employees), rather than activities. In Model III businesses are cross-classified by both activity and size, and then unit demand rates are estimated within each class. Data for model estimation were obtained by weighing waste deposited for collection by 435 businesses over a 25-wk period in the Portland, Oregon metropolitan region. Business size accounted for significantly more of the variation in unit demand rate than did business activity. This suggests that demand models used in planning solid waste collection and disposal systems can be improved by including indicators of business size.