Lexikon

Dense, Nonaqueous Phase Liquid, organic contaminants denser than water and do not dissolve or mix easily with water immiscible. It forms a separate phase pools in water. The pools containing chlorinated aliphatic solvents, chlorinated benzenes and phenols, polycyclic aromatic hydrocarbons and polychlorinated compounds serve as a long-term source for dissolved contaminant plumes. It is usually not easy to locate and identify them. Some of the DNAPL compounds can migrate through the clay layers as well providing a hazard for not only the subsurface waters but for the waters in the deeper layers as well. The following technologies can be used for the treatment: in situ thermal treatment, in situ bioremediation, in situ chemical oxidation = ISCO, application of co-solvents and tenzides to dissolve the ontaminants in the ground water, than pump and treat. Without additives the remediation of DNAPL-contaminated sites by pump and treat technology is time- and cost consuming.