11. In order to prevent soil and groundwater from being contaminated, contaminated soil burial sites may only be laid out on lands where the unconsolidated deposits on which the contaminated soils will be deposited are composed on their beds and walls of a natural homogenous layer having on a permanent basis a hydraulic conductivity equal to or less than 1 x 10-6 cm/s to a minimum depth of 3 m.
The zone on which the contaminated soils will be deposited shall be equipped, on their beds and walls, with an impermeabilization system with a double liner made up as follows:(1) a bottom protection level made up of an impermeable synthetic membrane of a high-density polyethylene type or having equivalent characteristics at least 1.5 mm thick, installed on the layer of unconsolidated deposits;
(2) a top protection level made up of an impermeable synthetic membrane of a high-density polyethylene type or having equivalent characteristics at least 1.5 mm thick.
The natural layer and the above-mentioned impermeable membranes must be laid out so as to have a slope of at least 2% to allow the flow, by gravity, of leachates towards the drains.