Abstract: A barrier of sheet metal elements in pile-driven into the ground in the path of contaminated groundwater. The barrier serves to funnel the contaminated water into an aperture in the barrier, in which is located a receptacle. A caisson is driven into the ground at the aperture, and the soil etc. removed from inside. A receptacle is lowered into the empty caisson, and a seal is provided whereby, when the caisson is removed the receptacle is sealed to the barrier. Baskets containing treatment material may be lowered into and hoisted out from the receptacle. Rubber seals seal the basket to the receptacle.

Abstract: For providing an in-ground system for treating contaminated groundwater, of the funnel-and-gate type, a cylindrical caisson is driven into the ground. The native soil is augered out of the caisson, and porous treatment material substituted. The caisson is then withdrawn, leaving a prism of porous treatment material in the ground. A sheet metal barrier element is inserted into the ground, one portion of the element extending into the prism and the other portion into the surrounding soil. More prisms are provided as further treatment gates, and more barrier elements are arranged to funnel the groundwater through the gates.

Abstract: Contaminated groundwater is treated in-situ, by funnelling the water through a gate or gates (23) in a watertight in-ground wall (18). Treatment material in the gate (23) breaks down the contaminant, or otherwise removes the contaminant from the flowing water. A removable caisson is first driven into the ground, excavated, and then a receptacle, for the treatment material, is lowered into the hollow interior.

Abstract: The joints between pile-driven sheet metal barrier elements (12, 14) have edge forms which interlock so as to form cavities (20, 21). The cavities extend from top to bottom of the barrier, and allow a flushing hose to be inserted to the foot of the barrier. Sealant is injected when the cavity is flushed clean. Two cavities are provided side by side at each joint. The cavities are independently sealed for extra reliability.

Abstract: The down-hole sampler comprises a reservoir, with screw-down type valves top and bottom. The valves are arranged with the axes of the screw threads vertical. The valve members are integral with the structure of the sampler, whereby even with the valves screwed open, the sampler and the valves remain structurally intact. The sampler has a very slim overall diameter (down to 6 mm) and yet the valves are easy to operate, and sturdy and reliable in operation. The sampler includes a surface-operated check-valve for admitting a water sample into the reservoir.