Evaluating the Pollutant Removal Efficiency of a New Retrofittable Sustainable Drainage Material
摘要
Urban transport runoff is a significant contributor to water pollution. It contains a mixture of pollutants which originate from sources including fuel combustion, fuel losses and oil leakages from hydraulic systems. This research sought to evaluate a new sustainable drainage material, known as BlueLay, for its pollutant removal efficiency. Initially, the hydraulic performance of the BlueLay was tested in terms of infiltration volume, absorption capacity and runoff compared with asphalt slabs of the same area. Building on these findings, a laboratory-scale pollutant test rig was constructed to evaluate the pollutant removal efficiency of BlueLay. The material was subjected to typical concentrations of Total Suspended Solids (TSS) (i.e., 75–774 mg/L) and a subset of heavy metals – Cadmium (Cd), Copper (Cu), Zinc (Zn) and Lead (Pb) found in road runoff under scenarios that replicated first flush and saturated overland flow events. The findings revealed that the range of TSS removal by BlueLay was >94% for all scenarios, and > 97% removal was achieved for saturated BlueLay. BlueLay in its dry state treated Pb (<145 μg/L), Cu (<110 μg/L), Zn (<315 μg/L) and Cd (<5 μg/L) to values well within the legislative (S.I. 272/2009) limits. For the highest applied concentrations of Cu (170 μg/L), Zn (600 μg/L) and Cd (10 μg/L), dry BlueLay exceeded the legislative limits by 1.4 μg/L, 9.2 μg/L and 0.4 μg/L respectively. In comparision, the exceedance from asphalt for the same metal concentrations, was approximately 100x, 50x and 20x larger. Future work includes testing pollutant removal efficiencies for a subset of Polyaromatic hydrocarbons.