METHOD OF WASHING TREATMENT OF OIL-CONTAMINATED SAND AND DEVICE THEREFOR

PROBLEM TO BE SOLVED: To easily wash oil-contaminated sand at a low cost. SOLUTION: In this washing treatment method, a surfactant and washing water are added to and mixed with oil-contaminated sand, and after the mixture is agitated under heated conditions, it is left standing in a sedimentation tank 12 to separate it into sand, water, and oil, each of which is recovered. Warm water is used as the washing water, and steam is blown into the mixture to heat it. The recovered water is further treated to circulate and reuse it as the washing water. This washing treatment device is provided with a mixer 1 for agitating and mixing the contaminated sand, the surfactant, and the washing water, a heating means for heating the mixture, and the sedimentation tank 12 for leaving the mixture discharged from the mixer standing to separate it into sand, water, and oil. As the heating means, boilers 5 and a heated water tank 6 for making the washing water warm water are used. Steam is blown into the mixer. A water treating device 18 for further treating the recovered water is provided. To the mixer, a concrete mixer truck is diverted.