The remediation of contaminated soils or sediments can be accomplished by a variety of methods: the material in question can be treated on site, removed altogether, or encapsulated.
Removal of contaminated sediments
Contaminated sediments are often removed from seabed and lake bottom sites by dredging. The muds collected in this way must be appropriately handled in order to facilitate subsequent treatment and disposal operations, and minimize the level of processing involved. The use of solutions such as SINTEXTUBE D tubular geofilters can provide a valid option for separation of the solid and liquid components on site. Solids of this nature will in general contain contaminants attached to soil particles, and may also absorb dissolved contaminants, with the addition of suitable reagents that favour their chemical and physical precipitation. Once dried to a shovelable consistency, the solids can be processed on site or taken away for disposal.
Encapsulation
In cases where contamination may be particularly extensive and the volumes of soil or sediment are such that treatment is not a viable option, the answer will be confinement. This consists in creating an impermeable barrier that isolates the contaminated area, disallowing contact with the surrounding environment. The protection of the impermeable layer can be provided by a non-woven geotextile such as GEODREN, which protects the geomembrane against damage from hard objects in the soil. Should it be necessary to capture and carry away water that could collect and create hydraulic pressure on the impermeable interface, this can be accomplished with the aid of drainage geocomposites such as SINTEXDRAIN, which replace the traditional drainage systems created with layers of aggregates.
