Development of methodology for quantifying collection ratio of post-consumer products based on material flow of steel

Some post-consumer products are not collected appropriately and are remained or disposed by unconventional methods. In order to conserve resources, the collection ratio of such products should be increased. To date, few definitive methods to quantify the collection ratio have been developed because the amount of dissipative products cannot be measured. In this paper, a new statistical method was developed to quantify the collection ratio of post-consumer products. This method is based on the identification of dynamic material flow of steel used in such products. The collection ratios of buildings, constructions, and machines were estimated. The amount of discarded post-consumer products during a year was calculated dynamically from their lifetime distributions and production history in which steel was used prior to that year. Uncertainty derived from the lifetime distributions was considered in the calculations. Finally, the collection ratios of the products were obtained with uncertainty as 1.00 (buildings), 0.00-0.22 (constructions), and 0.39-0.53 (machines).