FIELD: environmental pollution protection. SUBSTANCE: air is bubbled through contaminated ground dispersed in emulsion of organic solvent in alkali solution and simultaneously the total is ultrasonically treated. Operation is repeated until content of bis(9,10-dihydrophenarsasine)oxide in ground achieves 50-85 mg/kg. Organic solvent is then removed and remaining suspension is treated with an oxidant to convert bis(9,10- dihydrophenarsasine)oxide into soluble 9,10-dihydrophenarsasinic acid ammonium salt, after which purified ground is filtered off the ammonium salt solution. EFFECT: reduced consumption of organic solution, improved safety of process, and increased ground purification degree. 2 cl, 3 dwg
