Impacts of zeolite activation temperature and grain size toward bioretention system efficiency in removing Pb and Zn pollutant in stormwater runoff

Abstract

Stormwater runoff can be utilized as a clean water supply through a simple treatment technology such as a bioretention system. However, this water treatment efficiency is influenced by various factors. Previous research showed that although the bioretention system had combined with a plant and media composition, effluent concentration still exceeds the quality standard. This research aimed to improve the bioretention efficiency in removing heavy metal Pb and Zn in stormwater runoff. Three variations of bioretention were prepared, with the same combination of 2 types of plants (Chrysopogon zizanioides and Iris pseudacorus) and media composition (zeolite: quartz: compost: soil = 6:2:1:1). The zeolite activation temperatures and grain sizes simulated with three discharges variation of initial Pb and Zn concentration of synthetic stormwater runoff. The results showed that modified bioretention produced higher Pb removal efficiency (99.95% on average) and Zn (98.89% on average). Besides, the effluent concentrations have met the water quality standard following Government regulation No. 82/2001. In conclusion, the higher temperature of activated zeolite combined with smaller grain size significantly enhance the removal efficiency of Pb and Zn in stormwater runoff.