We recently developed an unique soil washing technology, which efficiently removes Pb and other toxic metals from soil by complexation with a strong chelant, EDTA. The patented technology features a novel reaction of alkaline substitution, precipitation and adsorption of toxic metals on polysaccharides and chelant acidic precipitation for process waters and EDTA recycling in a closed loop. No wastewaters and minimum (<1%) solid wastes are generated (US Patent 9108233, US Patent Appl. 2017/0100755A1). The post-remedial toxic emissions from soil are mitigated to the levels close or bellow limits of quantification by effective soil rinsing and addition of zero-valent Fe (Fe0) into the soil slurry (GB Patent Appl. 1720126.0) which enables for fast and permanent adsorption of small residual quantities of EDTA and toxic metals chelates.
Technology is cost-efficient by reagent recycling, using inexpensive/ waste materials (lime, H2SO4, waste paper, scrap iron) and common machinery. Realistically tended vegetable gardens with EDTA-remediated soil have supported the growth of vegetables, grasses and horticultural plants. Pb uptake by plants was prevented or significantly reduced.
The benefits of novel ReSoil soil remediation technology have been published in technical publications:
- FINŽGAR, Neža, JEŽ, Erika, VOGLAR, David, LEŠTAN, Domen. Spatial distribution of metal contamination before and after remediationin the Meza Valley, Slovenia. Geoderma, 2014, vol. 217/218, p. 135-143.
- VOGLAR, David and LEŠTAN, Domen. Chelant soil-washing technology for metal-contaminated soil. Environmental Technology, 2014, vol. 35, No. 11, p. 1389-1400.
- JEŽ, Erika and LEŠTAN, Domen. Prediction of blood lead levels in children before and after remediation of soil samples in the Upper Meza Valley, Slovenia. Journal of Hazardous materials, 2015, vol 296, p. 138-146.
- LEŠTAN, Domen. Novel chelant-based washing method for soil contaminated with Pb and other metals: A pilot-scale study. Land Degrad Develop. 2017, vol. 28, p. 2585-2595.