The Domestic Water Treatment Process

The domestic water treatment process is essential to ensure we have safe, great tasting and visibly clean water to drink. The steps in the process of creating fresh clean potable water is quite complex and relies on fields of expertise as in biology, chemistry, physics, mathematics and several others.

Below I’ve listed some of the processes your water endures before it reaches your sink.

  • Pretreatment: Before water enters the plant for domestic water treatment, it flows through intake screens that remove large objects such as plants, logs, dirt, rags, plastic as well as other particles that can be suspended in water.
  • Chemical Treatment: The water is than chemically treated. Then, chlorine, ammonia, and lime is injected into the untreated water. Chlorine and ammonia together form a chemical-chloramines- which disinfects the water by killing harmful bacteria and viruses. The lime actually is used to adjust the pH(acidity) of the water-which positively affects the reaction efficiency of the domestic water treatment process
  • Flocculation/Coagulation: the water is rapidly mixed with aluminum sulfate (alum) to evenly distribute the chemicals. The alum has a sticky surface and attracts and neutralizes particles and other impurities in the water to form large, heavy particles called floc. This process of the domestic water treatment process takes place in a flocculation basin where the water movement is slowed, and the floc is given time to form.
  • Sedimentation: The waters next stop is the Sedimentation basins, where the floc is allowed to settle to the bottom and the remaining particles are removed.
  • Filtration: Next, the water goes through a filtration process, in which it moves through large filters made of sand, gravel, and charcoal. This process of the domestic water treatment removes the microscopic suspended particles not removed during sedimentation. Because of the pH of the water and other chemicals present, particles become chemically attached to the filters and are removed from the water.
  • Disinfection/Secondary: One of the final steps in the domestic water treatment process is the use of chlorine in miniscule amounts is distributed to destroy any bacteria, pathogens and micro-organisms that can be present in the water. In addition to the chlorine, lime and fluoride are added. The chemicals help to adjust the pH and provide fluoride for dental care. Orthophosphate is also added to the water to prevent corrosion of water pipes.
  • Storage: As the final step in the domestic water treatment process, the water is held in large storage tanks until it is needed. As an additional disinfection process, ammonia and chlorine (chloramines) are added to disinfect against harmful bacteria and viruses that can collect in the storage tanks as well as collecting in the distribution plumbing. The water transfers through underground plumbing to residential and commercial facilities throughout the servicing community.

The completion of the domestic water treatment enables the clean drinking water to be delivered to homes and businesses through the water distribution system – a network of infrastructure that includes pipes, valves, fire hydrants, pump stations, and storage tanks.