Abstract: Leak prevention system for a liquid retention pond (10), the system comprising an upper membrane (3) to be covered by the liquid (1), a lower membrane (4) disposed on the bottom of the pond and joined in a sealed manner to the upper membrane on a peripheral portion to thereby form a normally sealed envelope (20) delimited by the two membranes, said envelope being filled with draining material (2), a plurality of passageways (6) disposed substantially horizontally in the draining material, a pumping device (5) adapted to generate an air vacuum in the drains, to suck leakage liquid that may have passed through the upper membrane, such that pollution of the surrounding soil is avoided in the event of a liquid leak through the upper membrane.

Abstract: Isolation and decontamination of a block of soil (1) containing at least one pollutant, a first array of drains (11) being placed substantially vertically in the block of soil, a first array of connectors (13) being connected to the drains of the first array of drains. The first array of connectors is selectively connected to a gas and/or fluid extraction system (10) or to an unpolluted-fluid injection system (10).