Water purification is the process of removing undesirable chemicals, biological contaminants, suspended solids and gases from contaminated water. The goal is to produce water fit for a specific purpose. Most water is disinfected for human consumption (
drinking water), but water purification may also be designed for a variety of other purposes, including fulfilling the requirements of medical, pharmacological, chemical and industrial applications. The methods used include physical processes such as
filtration,
sedimentation, and
distillation; biological processes such as
slow sand filters or
biologically active carbon; chemical processes such as
flocculation and
chlorination and the use of electromagnetic radiation such as
ultraviolet light.