Stormwater runoff volume reduction and pollutant removal efficiency via bioretention cell using rock wool as the media

Bioretention cells have been widely used in stormwater management. Media plays an important role in stormwater runoff reduction and pollutant removal. A novel bioretention media of rock wool has been proposed, and its effect on stormwater runoff reduction was investigated via a laboratory-scale experiment. The results showed that compared with the conventional bioretention (CB) using medium sand as media, the volume capture ratio of annual rainfall (VCRAR) of the rock wool bioretention (RWB) was 2.66-5.5% higher, and the peak flow reduction rate was 2.97-11.32% higher. The removal efficiency rates of the RWB on COD, NH4+ -N, TN, and TP were 25-30%, 10-31%, 20-40%, and 5-14% higher than the CB, respectively. The removal efficiency of the RWB on botht Pb and Zn was >99%. The microbial high-throughput sequencing results showed that the RWB can provide a better breeding environment for Bacteroides and Actinobacteria, which is conducive for the removal of pollutants. The RWB had a better stormwater runoff volume reduction rate and pollutant removal efficiency than the CB, therefore, it could be used as a better media for bioretention cells to improve stormwater management efficiency by using rock wool, obtained from construction waste, as the media.