Water wells are produced by drilling a borehole from the surface to an appropriate depth of a water bearing layer. Generally, the borehole must traverse a waterproof confining layer. When the confining layer is penetrated, fluids such as chemical contaminants can flow from the surface to the water bearing layer. When a well pipe casing is installed in the borehole, the well casing generally does not fill the entire borehole. The space between the periphery of the well casing and the wall of the borehole is generally filled with a non-waterproof aggregate. Therefore, most existing water wells, including those on farms where fertilizer and pesticide use is common, allow fluids to flow between the wall of the borehole and the well casing, past the penetrated confining layer, into the water bearing layer.
Even when water wells are abandoned, the process for abandoning and sealing a water well does not remedy the gap in the confining layer between the borehole wall and the well casing. Generally an abandoned water well is sealed by filling the well casing with bentonite and capping the well. However, contaminant fluids can percolate through soil down to the confining layer and flow laterally until reaching the point where the confining layer was penetrated by the borehole. The current process of sealing a water well therefore permits contaminants to flow into the water bearing layer, where they may be taken up by other, active wells.
Consequently, it would be advantageous if an apparatus existed that is suitable for remediating water wells and permanently sealing water wells that prevents contaminants from entering the water supply.