Methods for Treating Water

Coagulation

The water treatment process often begins with coagulation. To achieve coagulation, a positive-charged chemical is usually added to the water. Dissolved dirt and other particles with a negative charge are rendered neutral by the water’s positive direction. This causes the particles to connect with the chemicals, growing in size. Common ingredients in this process include salts, aluminum, and iron.

Flocculation

The subsequent flocculation stage follows coagulation. To create flocs, tiny particles in water are gently mixed. During this process, water treatment facilities may sometimes use extra chemicals to aid in the formation of flocs.

Sedimentation

One process used by water treatment facilities, sedimentation, removes particles from the water. Flocs are heavier than water. Thus they sink to the bottom during the sedimentation process.

Filtration

When the flocs have sunk to the bottom, the clear water at the top of the tank may be filtered to remove any remaining particles. The filtering process involves sending the clean water through a series of filters with varying pore sizes and constructions (such as sand, gravel, and charcoal). Dust, chemicals, parasites, bacteria, and viruses are all eliminated along with other dissolved particles by these filters. Activated carbon filters also eliminate bad scents.

Ultrafiltration may be used in conjunction with or as a replacement for conventional filtration in water treatment facilities. The water is filtered via a membrane with very tiny holes in a process called ultrafiltration. Water and other small molecules can pass through this filter (such as salts and tiny, charged molecules).

Osmosis in reverse

is a filtering process that may eliminate even more contaminants in water. Water purification plants often use reverse osmosis for the purification water.

Disinfection

To eliminate any leftover parasites, bacteria, or viruses, water treatment facilities may apply chemical disinfectants (such as chlorine, chloramine, or chlorine dioxide) after filtering the water. The chemical disinfectant is kept at a minimum before the water is released from the treatment facility and distributed to homes and businesses. Its residual disinfectant eliminates pathogens in the distribution system between the treatment facility and your tap.

Using ultraviolet (UV) light for water disinfection is an alternative to, or in conjunction with, using chlorine, chloramine, or chlorine dioxide in water treatment facilities. Although ultraviolet (UV) radiation and ozone effectively kill bacteria and other microorganisms in the water at the treatment plant, they lose their effectiveness as the water travels through the pipes to your faucet.