Water treatment systems have developed over the years in all countries to address the subject of safe and hygienic drinking water and water which can be used for industrial or other types of household or commercial activities. One of the subjects of pollution is water pollution and since this is a vital part of our existence, countries need to ensure that the water in communities is potable and free from pollutants as much as possible.
Water treatments thus describe those processes which are undertaken to make water more acceptable for the different end uses. Such uses include drinking water, water for various industrial processes, medical, household and other uses. The different water treatment processes share the same goal of removing contaminants from water or to reduce their concentration so that the water becomes fit for the various end uses. One vital use of water treatment systems nowadays is to send back the water to the natural environment without causing adverse ecological impact.
In water treatment processes, especially when it involves making water fit for drinking purposes, the solids separation process is used by different means such as settling or filtration and chemical processes which may be used are disinfection or coagulation. When waste water needs to be treated, various biological processes are used such as aerated lagoons, activated sludge or slow sand filters through which the water is passed to treat it effectively.
Water treatment is usually aimed towards purification of water. This is done by removing contaminants and to ensure that drinking water is fit for human consumption. Suspended solids, algae, fungi, bacteria and even minerals such as iron, manganese, sulphur and other chemical pollutants are removed to make water safe for drinking.
Water treatment systems also ensure that quality of water is maintained during conveyance and transport as well as distribution. Residual disinfectants are often left in treated water to prevent bacteriological contamination in the process of distribution.
For treating water to make it fit for drinking purposes, several methods are followed in different countries as per guidelines set down by the World Health Organization or WHO. Such processes consist of empty tanks for aeration to precipitate out iron residues; sand filter beds are made to remove precipitated iron. Pre chlorination is a process whereby biological growths in water are arrested. Coagulation, sedimentation are done to remove solids from water and finally filtration is opted to remove various suspended water particles.
These are the different ways in which water treatment occurs in different countries.