Decontaminating soil contaminated with chemical warfare agents

摘要

Process for cleaning land contaminated with chemical warfare agents, esp. those from the 1st and 2nd. World Wars belonging to the gp. of eye irritants, nose and throat irritants, skin-damaging agents and esp. organoarsenic cpds., and accompanying propellants, explosives, pyrotechnic formulations, by-products and decomposition prods., comprising a soil washing procedure with the stages of (I) wet sieving the contaminated material to separate the fraction with grains greater than 5 mm; (II) washing the contaminated material 0-5 mm in a washing drum at a temp. of 15-60 (40) deg. C, with a washing liquor of water, surface active materials, builders and vegetable oils for 10-60 (30) mins; (III) decanting the wash liquor and rinsing the washed soil and decanting off the rinse water 1-3 (2) times, the liqs. obtd. being collected in a stirred collection vessel; (IV) classifying out the grain fraction less than 0.1 mm and solid contaminants from the washed oil, and collecting the solids that have been separated off together with part of the classification water in the stirred collection vessel; (V) dewatering the washed classified soil (VI) working up the solid-liq. mixt. from the collection vessel by batchwise treatment with a reactive separating agent having absorptive action and dividing the mixt. into a sedimented sludge fraction and using the water in the washing and rinsing circuit, and dewatering the sedimented sludge; (VII) returning the washed classified soil to the site from where it was originally removed; (VIII) disposing of the dewatered sludge by thermal treatment and (IX) aspirating all parts of the appts. in which the soil and the wash liquor are in direct contact with atmospheric air and cleaning the effluent air.