Evaluation of water treatment residue as a soil substitute material compared to decomposed granite soil on the growth of greening trees

Abstract

The reuse of water treatment residue (WTR) as a soil substitute material instead of decomposed granite soil (DGS) on the growth of greening trees was evaluated. The pot experiment was performed on the trees (Acer palmatum, Cinnamomum camphora, Melia azedarach) to characterize the growth of the trees by using the WTR and DGS. In addition, physical properties of porosity, relative gas diffusivity (D/D₀), saturated hydraulic conductivities (K_S), plant-available water and bulk density (Bd), and chemical properties of pH, electrical conductivity, cation-exchange capacity (CEC), exchangeable bases, total-C and N, and plant-available phosphorus were analyzed for the WTR and DGS. The growth of the trees was better in the WTR than in the DGS, which was recognized to be due to the finding that D/D₀, K_S, total-N and CEC were higher in the WTR than in the DGS. Therefor, WTR is considered to be suitable as a soil substitute material for growing greening trees.