Water Treatment
Tap water must be processed to ensure it is safe to drink. The following water treatment stages detail the many steps through which raw or waste water is passed before it can enter our drinking water system once again. The exact stages of treatment always vary depending on the waters source. Does the water flow from a river or reservoir? Is it run-off from agriculture or farmland?
Outlined below are several water treatment stages in common use across the UK water industry.
Screening
Often the first stage is to remove large scale debris from the water. Water is essentially sieved using a course filter, allowing fine particles through but blocking larger organic matter.
Ozonation
Ozone treatment is common place across the UK. It helps to eliminate and destroy living organisms. Smaller scale ozone treatment also ensures an environmentally safe bacterial, viral and pathogen reduction method which is non-carcinogenic.
Coagulation
Following screening and ozonation, coagulation is the use of chemicals to bind smaller particles together into single clumps. This can then be removed in the next water treatment stage, clarification.
Clarification
Coagulated particles form a muddy sludge which seperates from the main body of water. This bulk of smaller coagulated particles is now removed leaving far fewer small to fine particles in the water.
Filtration
Further screening is required to remove persistant fine particles which have evaded previous treatment stages. Fine filtering media is used which must be regularly refreshed to ensure continued filtration. Filter water is now free from virtually all particles.
Correcting pH
Water pH is important to its physical and chemical character. pH may be adjusted at this stage.
Phosphate Dosing
This stage is a remedy to prevent water which contains low levels of calcium from contamination.
Chlorination & Storage
Finally water is chlorinated. This is an essential stage to protect treated water from becoming contaminated with bacteria or organisms before it reaches our household tap. Chlorinated water is then stored safely in vast tanks or reservoirs ready for our drinking water system.
