Glossary

Breakdown of biogenic material through micro-organisms in the absence of oxygen (anaerobic conditions). In the case of close co-operation between multiple groups of bacteria, biomass is transformed into biogas.

see Bioreactor

Sub-process of biological wastewater treatment in which the purified wastewater is separated from the sewage sludge involved in the cleaning process. Final clarification generally occurs in the secondary sedimentation tank. This part of a wastewater treatment plant is usually preceded by a biological stage (e.g. activated sludge basin), in which the flow velocity is reduced to bring about sedimentation of the degradable substances. Membrane procedures can also be used for final clarification under specific circumstances.

A procedure used in drinking water purification to reduce existing turbidity; insoluble substances are removed from the water in the form of large particles (flocs) through the addition of flocculants such as aluminium and iron salts in the form of chlorides and sulphates. The flocs are then separated by sedimentation, for example.

Large volumes of fat are produced during the slaughtering process, and this fat is separated from its carrier substance (water) in flotation plants. Flotation sludge is a mixture of fat, blood and water as well as other contaminants from the slaughtering process, such as feathers.

Something which is created (eroded), transported, deposited (sedimentation) or enriched (soaps) through the movement of water (river/stream). Taken from the Latin word fluvius = river. Fluvial sediments are usually well rounded and can comprise virtually all rocks found in the basin of the relevant river or stream.

The individual parts in a mixture of different substances (e.g. a liquid with a solid) are known as -> phases. The “free phase” is the part of a liquid (or gas liquid or gaseous phase) that is not bound (sorbed) to the solid parts of the mixture (solid phase) via bonding forces.

Funnel-and-gate systems consist of underground walls arranged to form a funnel, which channels the stream of contaminated groundwater into an underground gate, at the end of which the groundwater flow can continue as before. The water is cleaned as it passes through the system. If correctly configured, the procedure requires no pumps or additional power.