A Counter-Current Acid Leaching Process for the Remediation of Contaminated Soils from a Small-Arms Shooting Range |
| |
Authors: | Stéphanie Lafond Jean-François Blais Guy Mercier Richard Martel |
| |
Affiliation: | Institut National de la Recherche Scientifique, Université du Québec , Quebec , Canada |
| |
Abstract: | The objective of this research was to use a counter-current leaching process (CCLP) with leachate treatment to develop a remediation process for contaminated soils at a small-arms shooting range (SASR). The soil contaminant concentrations were 245 mg Cu kg?1, 3,368 mg Pb kg?1, 73 mg Sb kg?1, and 177 mg Zn kg?1. The CCLP includes three acid leaching steps (1M H2SO4 + 4M NaCl, t = 1 h, T = 20°C, soil suspension = 100 g L?1), followed by one water rinsing step (1 h). Seven counter-current remediation cycles were completed, and the average resulting metal removals were 93.2 ± 3.5% of Cu, 91.5 ± 5.7% of Pb, 82.2 ± 10.9% of Sb, and 30.0 ± 11.4% of Zn. The metal leaching performances decreased with the number of completed cycles. Soil treated with the CCLP with leachate treatment process met the USEPA threshold criteria of 5 mg Pb L?1 in the TCLP leachate. The CCLP allows a decrease of the water use by 32.9 m3 t?1 and the chemicals’ consumption by approximately 2,650 kg H2SO4, 6,014 kg NaCl, and 1,150 kg NaOH per ton of treated soil, in comparison to standard leaching processes. This corresponds to 78%, 69%, 83%, and 67% of reduction, respectively. |
| |
Keywords: | Contaminated soil small-arms shooting range acid leaching counter-current antimony heavy metal |
|
|