Method for detoxification treatment of soil

Abstract

A method for the detoxification treatment of a soil polluted by an organic chlorine-containing compound, which comprises incorporating an iron powder as a reducing agent into not only the soil present in the zone of saturation (4) under the groundwater level WL, but also the soil present in the zone of unsaturation (5) over the groundwater level or an excavated soil, by means of injecting and dispersing it together with a pressurized medium in the ground, blending it with soil by mechanical agitation, boring a hole from the ground surface and then introducing it into the hole by itself or as a blend with the extricated soil, or the like. It is preferred that the iron powder contains 0.1 wt % or more of carbon, that 50 wt % or more of the iron powder is a particle size sufficient to pass the 150 mum sieve, that the powder has a specific surface area of 500 cm<2> / g or more, and that the powder is added to soil in an amount of 0.1 to 10 wt %. The iron powder may contain copper, and an aqueous reducing material which is weekly acidic in water may be added together with the iron powder. Further, a gas (a) may be blown into a polluted region (6) to enhance the travel of the above contaminant.

Description

technical field [0001] The invention relates to the purification technology of soil polluted by organic halides. technical background [0002] Semiconductor factories and metal processing factories, etc. used a large amount of organochlorine compounds such as trichlorethylene that were discharged or discarded after use as a degreasing solvent in the past, and accumulated in the state of polluting soil or groundwater, and reused the factory land and the land in the surrounding area The development causes damage; the pollution of the groundwater by the accumulated organochlorine compounds also causes great social problems such as obstacles to the use of groundwater. [0003] In the publications of JP 2-49158, JP 2-49798, JP 2636171, JP 5-501520, and JP 6-506631, it is disclosed that the treatment with an iron-based metal reducing agent is polluted by this organochlorine compound. A method of decomposing pollutants into harmless water. [0004] The method in the Publication N...

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Problems solved by technology

Moreover, since the soil itself is not purified, it cannot eliminate the above-mentioned obstacles to land development, and it cannot be said to be a fully harmless treatment method.

[0010] (2) The groundwater purification method of metal-based reducing agents such as iron is aimed at groundwater saturation. It can neither prevent groundwater from spreading nor purify the soil itself without pollution. Therefore, it is not suitable for unsaturated zones above the groundwater level or soil after excavation. Purification, so the above method can not be said to be a fully harmless treatment method

[0013] (3) In the method of thermally decomposing the excavated soil at high temperature, large equipment for heating the soil must be used, and the soil particles themselves are deteriorated by heat, such as the function of the soil supporting the structure to enable the survival and reproduction of organisms to be damaged, so the treated soil Difficult to reuse

[0014] (4) In the biological remediation method, due to the characteristics of various soils, it is impossible to be suitable for all soils, even if it may be due to the action of microorganisms, the reaction is slow and long-term treatment is required

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