Comparison of the Effectiveness, Kinetics and Costs of Three Remediation Techniques for Agricultural Soils Historically Contaminated with Dieldrin, Using Laboratory Experiments

Félix Colin (1) , Grégory J.V Cohen (1) , Guillaume Aubert (2) , Cyril Aymonier (2) , Olivier Atteia (1)

1 Géoressources et environnement
2 ICMCB - Institut de Chimie de la Matière Condensée de Bordeaux

Organochlorine Pesticides (OCPs), as Dieldrin, are still present in agricultural soil continuing to be sources of contamination for growing crops. Soil remediation techniques using physicochemical processes are numerous in literature, but too few studies dealt with historically contaminated soils. Decontamination tests of a soil formerly contaminated with Dieldrin (100 µg kg-1) were conducted with three technics: (i) degradation by Zero-Valent Iron (ZVI) with or without additional reagents, (ii) Very Low-Temperature Thermal Treatment (VLTTT) and (iii) Supercritical Fluid Extraction (SFE) with CO2 to validate their effectiveness, compare their kinetics and estimate their costs. Each technique was implemented on soil samples during 0 to 70 days for the first technique and between 0 and 96 h for the two latter. Degradation showed efficiency up to 40% after 70 days, while SFE CO2 and VLTTT showed a decrease of 85% of the initial Dieldrin concentration in the soil after only 4 and 24 h, respectively. First-order kinetic models have been associated for each remediation techniques with kinetic constant k ranging from 9.3×10-4 to 8.1×10-1 h-1 and quickness of these techniques could be classified as: ZVI < VLTTT < SFE. The cost of each technique has been estimated for one ton of soil, calculating the price of each reagent and the energy required. VLTTT and SFE appear to be the two most cost-effective techniques tested for decontaminating soils formerly contaminated with Dieldrin. Some suggestions for improving the processes and reducing costs are given, but future research is needed to validate these optimisations, to identify scaling-up issues and also to ensure that the soil agronomic properties of the soil are not altered.

Mots clés: Aged Dieldrin contamination; Soil remediation; Thermal Treatment; ZVI degradation; SFE CO2

Domaines: Matériaux

Félix Colin, Grégory J.V Cohen, Guillaume Aubert, Cyril Aymonier, Olivier Atteia. Comparison of the Effectiveness, Kinetics and Costs of Three Remediation Techniques for Agricultural Soils Historically Contaminated with Dieldrin, Using Laboratory Experiments. 2022. ⟨hal-03763659⟩