Education

How we clean our water

How does South Staffs Water clean the water from its main reservoir?
Screening
Water flows through a screen (bars that fit over the outlet pipe). These screens prevent large objects such as tree branches, bottles or rubbish from entering and therefore blocking the outlet pipe. The pipes then take the water from the reservoir to the treatment works.

Clarification (making the water clearer)
At the treatment works, water is put into large tanks and a coagulant (this is called PAC – poly aluminium chloride) is added. The PAC joins with the particles causing them to stick together. The dirt particles then stick together with other particles. This is called flocculation.

Our Treatment Works at Seedy Mill uses two different methods to make the water clearer.

One method sinks the dirt particles and the other releases high pressure water and air into the water to float the dirt particles to the top of the water.

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In this method, high pressure water and air is released into the water causing the dirt particles to float to the top to form a 'mousse' at the top of the water. The sedimentation process creates a 'chemical blanket' in the bottom of the tank which water then passes through, removing more of the dirt particles.

Both processes remove dirt particles, algae and colour from the water that has come from the reservoir.

Filtration
Water passes through granular activated carbon filters which remove any remaining particles. The particles stick to the surface of the carbon grains. Any final impurities in the water are also removed by carbon filters.

Disinfection
Water from the filters is collected in large underground tanks where chlorine is added. The water then passes through ultra violet disinfection to ensure that any bacteria or germs are killed. A small amount of chlorine is left in the water to continue to kill any bacteria if they get into the network of underground pipes.

Fluoridation
Fluoride is added to the water at the request of the Health Authority as it is believed to reduce tooth decay.

Distribution
Using a vast network of underground pipes, clean, safe water is delivered to your home, school and place of work.