Heavy metal removal efficiency in a kaolinite-sand media filtration pilot-scale installation

An experimental study was developed in order to evaluate the efficiency in retention of heavy metal from highway runoff using for filter bed current construction materials with known proprieties, sand and kaolinite. The control parameters for the experiments were: pH, conductivity, temperature, Zn, Cu, Pb, flow, and hydraulic head. Preliminary results show that Zn is the most mobile metal with retention efficiency values decreasing to less than 50% in a 15-, 70-, and 110-day period, for the three different filter media. For Cu and Pb, and after a period of 260 days, the retention efficiencies obtained were above 70% and 40%, respectively, and above 90% in the sand and kaolinite media.