| Abstract: | Remediation with chelants can restore metal‐contaminated soils for use as a natural resource. Calcareous soil from Meza Valley, Slovenia, and acidic soils from Arnoldstein, Austria, and Pribram, Czech Republic (with 1,028, 862, and 926 mg ∙Pb∙kg−1, respectively), were washed with 60–100 mmol EDTA per kilogram of air‐dried soil in series of 30 batches (50 kg soil batch−1). The approach involves a novel reaction that incorporates alkaline substitution, precipitation and adsorption of toxic metals on polysaccharides, and chelant acidic precipitation via 83% EDTA (on average) and complete process water recycling (no wastewater was generated). The pH gradient was imposed by Ca(OH)2 and H2SO4, and excess reagent was removed with the remediated soil as CaSO4, thereby preventing the salification of the recycled waters. Remediation removed 60%, 78%, and 71% of the Pb from the Meza, Arnoldstein, and Pribram soils, respectively, and reduced the Pb bioaccessibility levels in the simulated human gastrointestinal phase by 5.0, 7.7, and 8.1 times. Residual emissions (EDTA, toxic metals) were reduced with soil aging and remediated soil deposition on a reactive permeable barrier. The solid waste generated from the process totaled 10.8 kg tons−1 of the air‐dried soil, and the material/energy costs of remediation reached 20.6 € tons−1. These results demonstrate the robustness, efficiency, and safety of this novel approach. |
