Development of the WEEE grouping system in South Korea using the hierarchical and non-hierarchical clustering algorithms

Abstract

South Korea has been operating an extended producer responsibility system (EPR) since 2003 to collect, transport, and dispose of e-waste. Until 2019, the EPR system was operated with a total number of 27 electronic products classified into five categories based on weight and volume, but 23 items will be added in 2020 along with a change to five categories based on the function of the products. In this study that used actual operational data related to the collection, transport, and recycling steps from recycling plants in South Korea, we have analyzed how well the new five-category grouping appropriately reflected actual recycling industrial conditions and have provided optimal classification alternatives. The results showed that clustering accuracy was the best for the classification that used the hierarchical method. In particular, the evaluation index, silhouettes, showed the best accuracy with three clusters (0.4155), and the Dunn index indicated the best performance with four clusters (0.2333). Based these results, ANOVA tests were implemented, and showed that the three clusters in the relevant models were significantly different with regard to takt-time, weight, volume, and no. of recycling processes (p <= 0.01) and to both recycling cost and value of material (p <= 0.05). In contrast, with regard to the grouping suggested by the South Korean government, the overall results of the clustering accuracy using silhouettes and Dunn indices were -0.2028 and 0.058, respectively. In conclusion, the new grouping suggested by the hierarchical method with four clusters can be utilized as a political decision-making tool.