Water undergoes several treatment processes before being distributed through the drinking water system. What are they? Learn about the different stages of water treatment.
The treatment of raw water after it is collected depends on its quality and its constituents, which vary over time. Water drawn from the environment must therefore be continuously analyzed before undergoing the appropriate treatment to make it safe to drink.
Once this test is completed, the water undergoes several treatments before being distributed through the drinking water system.
Screening and Sifting
As the collected water passes through grates and screens, the largest pieces of debris are removed.
Oxidation
If the organic load is very high or if there is’ammonia, from the iron or the manganese in solution, the’oxidation facilitates their removal during the clarification phase. This oxidation step can be carried out using chlorine or the’ozone.
Clarification: Coagulation-flocculation, settling, and filtration
In the presence of coagulants and flocculants, the particles suspended in the water clump together to form flocs. The weight of these flocs causes the sedimentation particles at the bottom of the basins settling. The filtration final treatment through mineral filters (sand) or membranes makes it possible to produce crystal-clear water free of particles.
The water cycle, from collection to treatment. © Pierre-Alain Dorange / SIEAAC Cognac CC by-nc 2.0
Disinfection
The bacteria and viruses pathogens Those that remain in the water are removed during the disinfection process. Chlorine, ozone, or ultraviolet rays. A small amount of chlorine remains in the treated water to prevent bacterial growth further downstream in the water system.
Other Treatments
Eventually, the hardness The water is treated to prevent corrosion or the scaling of the pipes.
In the case of specific types of pollution, such as nitrate pollution or pesticides for example, some pollution control treatments Additional fees apply.
Upon leaving the water treatment plant, the water is transported to reservoirs (water towers) and then on to the faucets.
