Dense non-aqueous phase liquid

A heavy phase is in the ecology of a water-insoluble liquid with a density greater than water ( ρ > 1 ), hence the Anglo-American usage, the abbreviation DNAPL ( dense non Aqueous phase liquid) is commonly used. Immiscible liquids are stacked in clearly separated phases, such as water and oil.

Almost all chlorinated hydrocarbons ( CHCs) are such heavy phases, and especially for the volatile representative of halogenated hydrocarbons ( HHC ), abbreviated as VOC, the DNAPL behavior plays an important role in the context of groundwater pollution.

You get depends on the material properties and the soil into the groundwater. There, the organic phases dissolve, but it takes at concentrations of a few 100 to a few 1000 mg / l of decades to centuries. The dissolved water CKW not fall off, but are more prevalent and under certain environmental conditions caused critical degradation products such as vinyl chloride, which accumulate.

Practically DNAPL broad rarely up in the rock below the groundwater sole and penetrate only at large exit quantities of CHC on a 10 meters into the ground. The horizontal spread is massive and from the higher layers seep permanently Volatile halogenated hydrocarbons ( CHC ) to, resulting in a high contamination density results. In addition, CHC - phase body shall specify in the rock, making a targeted removal impossible. The reorganization measures shall be limited to methods such as pump and treat or reactive systems.

The DNAPL behavior of the CHC is mainly responsible for the high groundwater contamination potential because they spread slowly and far. In addition, they are difficult to impossible to remove up from the underground. Thus, the groundwater can be contaminated for decades or centuries.