How is water treated to make it safe to drink?

Water is treated through a series of processes including coagulation, sedimentation, filtration, and disinfection to make it safe to drink.

The treatment of water to make it safe for drinking involves several stages. The first step is coagulation, where chemicals are added to the water to bind together the small particles of dirt and dissolved particles into larger particles called 'flocs'. These chemicals, often aluminium or iron salts, neutralise the charge on the particles allowing them to stick together.

Following coagulation, the water moves into sedimentation basins where the heavy flocs settle to the bottom due to gravity. This process is known as sedimentation. The settled flocs form a layer of sludge which is then removed, leaving cleaner water to move on to the next stage.

The next step is filtration, where the water is passed through filters made of sand, gravel, and charcoal to remove even smaller particles. The filters work by trapping the particles in the tiny spaces between the grains of sand or charcoal. This process removes almost all of the particles that might still be present in the water.

The final stage in the water treatment process is disinfection. In this stage, chemicals such as chlorine or ultraviolet light are used to kill any remaining bacteria, viruses, or other microorganisms in the water. This ensures that the water is safe to drink and free from harmful organisms.

Throughout the treatment process, the water is constantly monitored and tested to ensure it meets the required safety standards. The process may vary slightly depending on the source of the water and the specific contaminants present, but the goal is always to produce clean, safe drinking water.