The process of removing carbon dioxide from water, using contact towers or air scrubbers.

To draw off the upper layer of liquid after the heaviest material (a solid or another liquid) has settled.

The break down of organic matter by bacteria and fungi, to change the chemical structure and physical appearance of matter.

The removal of fluoride from drinking water to prevent teeth damage.

Chemicals that are added to wastewater discharges to prevent the water from foaming when it is discharged into a receiving water body.

The process of removing dissolved gasses from water, using vacuum or heat.

Process that serves to remove all ionised substances from a solution. Most commonly is the exchange process where cations and anions are removed independently of each other.

Processes to remove minerals from water, usually the term is restricted to ion exchange processes.

Demineralised water. Water that is treated to be contaminant-, mineral- and salt free.

Removal of nitrate and nitrate product from water to produce a quality that answeres common water standards.

The weight of a certain amount of water. It is usually expressed in kilograms per cubic metre.

The storage of water in low areas, such as ponds, and wetlands.

Treatment process in which the entire filter bed is used to trap insoluble and suspended particles in its voids as water flows through it.

The removal of salt from seawater or brackish water to produce drinking water, using various techniques.

The opposite of adsorption; the release of matter from the adsorption medium, usually to recover material.

The actual time that a small amount of water is in a settling basin or flocculating basin. In storage reservoirs, it means the length of time water will be stored.

A water-soluble cleansing agent, other than soap.

The separation of water from sludge, to produce a solid cake.

A component of the ozone contacting system in an ozone generator that allows diffusion of an ozone containing gas.

The movement of gas molecules or aerosols into liquids, caused by a concentration gradient.

A closed tank for wastewater treatment, in which bacterial action is induced to break down organic matter.

Distilled water that has been stabilized, buffered, and aerated. It is often applied in the BOD tests.

Water that flows from the ground surface directly into streams, rivers, and lakes.

Flow of surface water in a stream or canal.

Fluids or gasses to disinfect filters, pipelines, systems, etc.

The decontamination of fluids and surfaces. To disinfect a fluid or surface a variety of techniques are used, such as ozone disinfection. Often disinfection means eliminating the present microrganisms with a biocide.

The process during which solid particles mix molecule by molecule with a liquid and appear to become part of the liquid.

A procedure of induced flotation with very fine air bubbles or ‘micro bubbles’, of 40 to 70 microns.

The amount of oxygen dissolved in water at a certain time, expressed in ppm mg/L.

Solids material that totally dissolves in water and can be removed by means of filtration.

Water treatment method where water is boiled to steam and condensed in a separate reservoir. Contaminants with higher boiling points than water do not vaporize and remain in the boiling flask.

Cleaning, deepening, or widening of a waterway, using a machine (dredge) that removes materials by means of a scoop or a suction device.

Term applied to periods of less than average precipitation over a certain period of time.

Two separate samples with separate containers taken at the same time and at the same place.

Acidic bodies of water that contain many plants but few fish, due to the presence of great amounts of organic matter.