Application of carbon dioxide in remediation of contaminated soils, sediments and aquifers

摘要

The object of the invention is the application of carbon dioxide (CO 2 ) at gaseous or liquid state in remediation of contaminated soils, sediments and aquifers. In particular the application is based on the exploitation of physical and chemical properties of carbon dioxide in promoting the desorption and/or dissolution of the organic and/or inorganic contaminants from soil/sediments matrices. The mechanisms of desorption and/or dissolution by carbon dioxide allows to obtain: - extraction and/or recovery of the contaminants; - transport of contaminants from deeper layers to more superficial layers of the soil; - availability of contaminants for subsequent removal processes (biological, chemical and/or physical processes). The application covers remediation systems in-situ, on-site and ex-situ. In case of in-situ treatment, the invention relates to the injection and/or diffusion of carbon dioxide in the saturated and/or unsaturated soil. Carbon dioxide can be injected into the ground in gaseous or liquid form. In case of on-site or ex-situ treatment, the invention relates to the injection/diffusion of carbon dioxide in excavated soil or dredged sediment, collected in heaps or sent to dedicated reactors. Carbon dioxide can be injected into the soil and sediments in gaseous or liquid form. In all cases, in-situ, on-site or ex-situ, carbon dioxide can be injected pure or mixed and/or combined with other inert, oxidants and/or reducing gases.