Water treatment encompasses the processes used to make water suitable for its intended use, including drinking, industrial, irrigation, or environmental discharge. It involves physical, chemical, and biological methods to remove contaminants.
Water treatment refers to the series of processes applied to raw water to remove or reduce contaminants to levels appropriate for its intended use. Conventional drinking water treatment typically follows a multi-barrier approach: coagulation and flocculation (adding chemicals to aggregate fine particles), sedimentation (gravity settling of flocs), filtration (passing water through granular media such as sand and anthracite), and disinfection (using chlorine, chloramines, ozone, or UV light to inactivate pathogens). Advanced treatment processes include activated carbon adsorption for organic contaminants and taste/odor compounds, membrane filtration (microfiltration, ultrafiltration, nanofiltration, reverse osmosis), ion exchange for hardness and specific ion removal, and advanced oxidation processes. Wastewater treatment generally progresses through primary treatment (physical settling), secondary treatment (biological processes such as activated sludge), and tertiary treatment (nutrient removal, advanced filtration). The selection of treatment processes depends on raw water quality, regulatory requirements, target end use, and economic considerations. Water treatment is one of the greatest public health achievements of the modern era, having dramatically reduced the incidence of waterborne diseases in communities with access to treated water supplies.