Soil gas and groundwater remediation system and method

A system for intercepting, treating and venting vapors from contaminated soil in a vadose zone that extends downwardly from a ground level to a water table and from contaminated groundwater below said water table, comprising:

• a large borehole with a selected diameter, said large borehole having a top end at said ground level, a spaced bottom end at a selected depth and an inwardly facing outer wall of soil extending downwardly from said top end to said bottom end, said large borehole defining a borehole cavity, said top end being open to atmosphere above said ground level to allow unimpeded flow of gases, said large borehole having a mesh liner against said outer wall and around said borehole cavity from said top end to said bottom end and porous fill material inside said liner and filling said borehole cavity, said fill material having a porosity at least an order of magnitude greater than said soil, said fill material including materials to retard and degrade contaminants in said vapors, said fill material including at least one of organic carbon, reactive iron and nutrients for microbial activity, said large borehole having a hollow, slotted aeration tube having a diameter smaller than said large borehole, said tube extending through said fill material from said top end towards said bottom end of said large borehole, and
• at least one small borehole spaced from said large borehole and having a selected diameter significantly smaller than said diameter of said large borehole, said small borehole having a top end at said ground level, a spaced bottom end at a selected depth and an inwardly facing outer wall of soil extending downwardly from said top end to said bottom end, said small borehole defining a borehole cavity, said top end being open to atmosphere above said ground level to allow unimpeded flow of gases, said small borehole having a mesh liner against said outer wall and around said borehole cavity from said top end to said bottom end and porous fill material inside said liner and filling said borehole cavity, said fill material having a porosity at least an order of magnitude greater than said soil,
• whereby variations in atmospheric barometric pressure pull said vapors from said groundwater and said soil to said borehole cavity of said large borehole and out said top end of said large borehole.

A method for intercepting, treating and venting vapors from contaminated soil in a vadose zone that extends downwardly from a ground level to a water table and from contaminated groundwater below said water table, comprising the steps of:

• providing a large borehole with a selected diameter, said large borehole having a top end at said ground level, a spaced bottom end spaced at a selected depth and an inwardly facing outer wall of soil extending downwardly from said top end to said bottom end, said large borehole defining a borehole cavity, said top end being open to atmosphere above said ground level to allow unimpeded flow of gases,
• installing a liner of porous material in said large borehole against said outer wall and around said borehole cavity from said top end to said bottom end,
• filling said borehole cavity of said large borehole inside said liner with porous fill material,
• providing at least one small borehole with a selected diameter, said small borehole having a top end at said ground level, a spaced bottom end at a selected depth and an inwardly facing outer wall of soil extending downwardly from said top end to said bottom end, said small borehole defining a borehole cavity, said top end being open to atmosphere above said ground level to allow unimpeded flow of gases,
• installing a liner of porous material in said small borehole against said outer wall and around said borehole cavity from said top end to said bottom end,
• filling said borehole cavity of said small borehole inside said liner with porous fill material,
• injecting atmospheric gases into said borehole cavity of said small borehole and into said soil with variations in atmospheric barometric pressure and,
• pulling said vapors from said groundwater and said soil to said borehole cavity and out said top end of said large borehole with variations in atmospheric barometric pressure.