METHOD FOR CLEANING SOIL

PROBLEM TO BE SOLVED: To provide a method for cleaning soil, in which contaminated soil can be cleaned easily while reducing a cleaning cost regardless of the presence or absence of a ground facility.SOLUTION: The method for cleaning soil comprises: an observation well formation step of forming an observation well 10 in the soil S containing at least one contaminant of oil, volatile organic compounds, heavy metals and cyan compounds; an injection well formation step of forming an injection well 11 on the outer peripheral side of the observation well 10; a measurement step of measuring an oxidation-reduction potential of the soil S in the observation well 10; an injection step of injecting high-concentration oxygen water into the soil S from the injection well 11 as an injection liquid L so that the measured oxidation-reduction potential becomes a value which is suitable to activity of microorganisms in the soil S and falls within a predetermined range; and a cleaning step of cleaning the soil by decomposing the contaminants by the microorganisms. 【課題】コストを抑えつつ、地上設備の有無によらず、容易に汚染土壌の浄化を行うことが可能な土壌浄化方法を提供する。【解決手段】油、揮発性有機化合物、重金属、及びシアン化合物のうちの少なくともいずれか一種の汚染物質を含有する土壌Ｓに観測井戸１０を形成する観測井戸形成工程と、観測井戸１０の外周側で土壌Ｓに注入井戸１１を形成する注入井戸形成工程と、観測井戸１０で土壌Ｓの酸化還元電位を計測する計測工程と、計測された酸化還元電位が土壌Ｓ中の微生物の活性に適した予め定めた所定範囲内の値となるように、注入井戸１１から土壌Ｓに注入液Ｌとして高濃度酸素水を注入する注入工程と、汚染物質を微生物によって分解して浄化する浄化工程とを含むことを特徴とする。【選択図】 図２