Without water, there is no life, no plant growth, and water is essential in numerous other processes as well – Part 2
Apart from domestic use and watering in agriculture and horticulture, the best-known use of water is in hydroelectric power plants. There the medium water is used for the drive of turbines. In this process, the existing position energy is converted into electrical energy. Wahrend in Kleinkraftwerken (deren Generatoren luftgekuhlt sind) das Wasser mit der Nutzung nicht erwarmt wird, mussen die Generatoren bei groben Flusskraftwerken mit Wasser gekuhlt werden. In some power plants, the heat generated is not released to the river water, but is used in a local heat network.
Part 1: Water – from where, to where, to where
Drinking water and water treatment
In Germany, the consumption of bottled water has increased significantly in recent years, although drinking water from the public water supply is not only subject to more frequent controls, but also has to comply with lower limits than bottled water. In fact, when setting the limits, the frequency of use is also taken into account, and in the case of drinking water, it is amed that it is used very often for drinking and cooking. In practice, however, this use accounts for just 3% of drinking water consumption. In the case of mineral water, the limits may be higher because mineral water, which is subject to 19 percent VAT, is not considered a staple food and the consumption of bottled water, it is amed, occurs much less frequently than the consumption of tap water.
The water treatment for the public water supply in Germany is carried out by about 6.300 water supply companies made. These are companies of different size, legal form and ownership structure.
The starting point of drinking water treatment is the raw water. Raw water is normally defined as the groundwater required for drinking water supply. The quality of the raw water should correspond as far as possible to the quality of drinking water, so that the expenditure necessary for the water treatment in the water works can be minimized. In order to support this goal, the catchment areas of groundwater catchments are protected by the designation of water protection areas. Raw water quality is constantly monitored by sampling both at the receiving wells and at upstream monitoring points.
Water treatment is used to adapt raw water to the requirements of drinking water use. It is the treatment of raw water in various processes using physical, chemical and biological techniques in order to adapt its properties to its intended use as drinking water. The purpose of drinking water treatment is not to provide customers with certain medications (such as fluorine or iodine), but to change it so that it meets the requirements of the drinking water ordinance.
In many cases, the treatment of spring or surface water is more costly than the treatment of drinking water from groundwater. Here mostly an ozonation with following sedimentation and a filtering by means of activated carbon is used. Finally, the water is disinfected.
Photo: Roger McLas. License: CC BY-SA 3.0.
However, with the increased introduction of medicines into the waters, new challenges are coming to water utilities. The concentration of pharmaceutical preres in flowing water, such as that used for drinking water, is already said to be about the same as the pollution caused by pesticides. In addition to the individual active ingredients, their metabolites (degradation products) and the combination of different active ingredients and degradation products also play a role.
The processes taking place here are still largely unknown. New active ingredients and combinations of active ingredients coming onto the market, as well as biotechnologically developed drugs, continue to complicate research in this area. The report that significant amounts of cocaine are now also found in drinking water was obviously due to a fundamental confusion. Traces of cocaine were found in waste water in the course of a study and then extrapolated for the whole of Germany.