Evaluation of the recyclability of construction and demolition waste fines as a garden substrate and soil amendment agent: a case study from the Republic of Korea

Construction and demolition waste fines (CDWF) account for approximately 15% of landfill waste, and are likely to generate H₂S during decomposition. In Korea, CDWF disposal depends mostly on landfill sites. Therefore, the purpose of this study was to investigate the possibility of using CDWF as a substrate for plant growth or soil amendment agent for the improvement of reclaimed land. Experiments were conducted on the growth of three plant species in garden soil mixed with CDWF. Because of the high salinity of CDWF, the heights of all plants decreased as the mixing ratio of CDWF increased. However, the Chrysanthemum morifolium growing in only CDWF showed similar or slightly lower dry weight compared to the control specimens. Upon evaluating the applicability of CDWF to the improvement of reclaimed soil with a column test, the saturated hydraulic conductivity (K_sat) and removal rate of cations from the soil were found to increase as the CDWF mixing ratio increased because of the Ca²⁺ contained in the CDWF. These results suggest that it is possible to reduce both the amount of landfill and the H₂S generation using previously landfilled CDWF.