The invention discloses a method for treating heavy
metal pollution in soil by using a low-position leaching high-position extraction technology. The method comprises: constructing a packed drain well, laying a clay working
bed course on the
earth surface, arranging a leaching agent
pipe in the packed drain well, arranging a vacuum filtering
pipe in the vertical direction of the working
bed course, digging a
ditch groove, laying a
plastic film on the upper portion of the working
bed course, drilling at the positions, corresponding to the leaching agent
pipe and the vacuum filtering pipe, on the
plastic film, preparing a
carbon dioxide leaching agent, introducing the
carbon dioxide leaching agent into the leaching agent pipe, controlling the flow rate of
carbon dioxide while opening a vacuum
system, controlling the vacuum degree and the leaching agent introducing time, and controlling the
vacuum extraction time. According to the present invention, the leaching process and the extractionprocess are performed simultaneously, wherein carbon dioxide diffuses upward to accelerate and expand the range of the
bicarbonate forming soil so as to achieve the complete leaching treatment, and the heavy
metal salt in the mellow soil layer cannot migrate downward due to the migration effect of the
vacuum pressure so as to effectively prevent
groundwater and soil from being polluted by the heavy
metal salts.