LOW IMPACT DEVELOPMENT MIXTURE EVALUATION FOR HEAVY METAL REMOVAL

Abstract

To address non-point heavy metal pollutant sources to urban stormwater runoff, the LIDMATTM (Low Impact Development MAT) is a stormwater management runoff system designed and manufactured for effective treatment for heavy metals. The LIDMATTM contains approximately 70% sand, 25% manure compost, and 5% steel slag by mass. The LIDMATTM was evaluated based on flow rate, pH, heavy metal removal, and the concentrations of N and P leached; conditions for optimum removal have been quantified. For treating synthetic stormwater runoff, 12 trials were completed using bench-scale and column media testing systems. Average effluent event mean concentrations of all trials were 25 ± 10 μg/L Cu, 21 ± 13 μg/L Pb, and 57 ± 42 μg/L Zn from studies at influent concentrations of 500 μg/L, 300 μg/L, and 100 μg/L, which satisfy Numeric Action Levels (NALs) of Cu, Pb, and Zn by the state of California, USA, Industrial General Permit (IGP). The leaching of nitrogen and phosphorous were also below the NALs.