14.2  Water treatment

The purpose of water treatment is to reduce or remove all contaminants that are present in the water and to improve water quality so that it is completely safe to drink. Water is unlikely to be completely free of contaminants at the original source. The types of water treatment processes depend on the characteristics of the raw water (untreated water direct from its source) and required water quality standards. Suspended solids, bacteria, algae, viruses, fungi, minerals such as iron and manganese, and fertilisers are among the substances that are removed during water treatment. (Suspended solids are tiny particles of solid material that are carried along or suspended in the water.) Effective treatment should ensure the removal of all disease-causing agents and so reduce the possibility of the outbreak of waterborne disease.

Water treatment systems can be categorised as small-scale water treatment, which includes community and household treatment methods, or large-scale water treatment that might be found in towns and cities.