Glossary

See: Tetrachloroethylene.

Measure of the ability of a porous material, such as rock or soil, to allow gases or fluids to pass through it.

A phase is a spatial area in which the physical parameters and chemical composition of the relevant matter are homogeneous.

Surfaces on which (sun)light breaks down organic materials.

Measure of the level of contamination of commercial/industrial wastewater, specified as the number of persons producing a corresponding pollution load.

Group of toxic substances used up to the 1980s, primarily in transformers, capacitors and hydraulic systems; PCBs were also used as softening agent in paints, sealing compounds and plastics. The substances have since been included in the “dirty dozen” group of known organic toxins, which were banned throughout the world in 2001. In addition to their chronic toxic effect (chloracne, hair loss and hyperpigmentation), PCBs are also suspected of being carcinogenic and hormonally active.

Group of organic compounds. PAHs are natural components of coal and crude oil that are created during the pyrolysis (incomplete combustion) of organic material (e.g. coal, heating oil, fuel, wood, tobacco) and are thus ubiquitous in the environment. Due to their degradation resistance, toxicity and prevalence in the environment, PAHs are considered highly potent pollutants.

Substance that separates from a solution and settles (precipitation).

In this process, chemical reactions cause the transformation of dissolved substances into insoluble substances, which then settle at the bottom of a vessel or water body – e.g. in the form of flocs – where they can be more easily removed from the water.

Potassium permanganate (KMnO4) is a powerful oxidising agent (see also ->ISCO), which can be used in drinking water purification (e.g. to remove iron) and to oxidise sulphite into sulphate.

Membranes are fine filters that allow liquids to pass through but retain the contained substances. In a pressure-driven membrane process, the liquid is pressurised when transported through the membrane. Depending on the cut-off or pore size of the membrane, the processes micro-, ultra- and nano-filtration as well as reverse osmosis are distinguished.

With this procedure, the water is artificially “marked” (e.g. with a colourant) in order to monitor its flow behaviour (e.g. flow velocity).

Remediation procedure in which the contaminated groundwater is extracted via wells or drainage systems before being cleaned.