At Genesis Drainage, we offer drainage services in Hereford and surrounding towns. Every time you turn on the tap and fill your glass with water, have you ever stopped to ask yourself what the water has to go through before it gets to your tap? Lucky for you, you’re at the right place to get your answers.
When the water first arrives at the treatment plant, it has to be screened. It is passed through a series of metal bars and screens. The aim is to trap any large debris like water plants, small water animals, litter, leaves and other large enough contaminants.
Water contains clay, silt and sand. The particles are way too small to be trapped in the metal bars or the screens. To get rid of them, slacked lime is added to the raw water. Because the sand particles have a negative charge in them which makes them repel each other, the water is moved around at a very high speed in what is called a spiral flocculator. This helps to improve the contact between the slacked lime and the water. The role of the lime is to neutralise the charges in the particles making them attract each other. The process of attracting each other is known as coagulation.
During this process, all the contaminants which include the silt, smaller water plants and even all the bad minerals coagulate and form what is called ‘floc.’
This process is aimed at helping the floc to settle down and become easier to get rid of. The water and the floc flow slowly into a big tank called the sedimentation tank. While here, the floc settles down to the bottom and is now referred to as sludge.
To get rid of the sludge, it is sucked out by the desludging bridges and sent to a sludge deposit site. At this point, the water looks much cleaner but not yet safe for drinking.
The water from the sedimentation tank then flow into yet another tank for called a carbonation tank. At this point, the water has a pH of about 10.5 because of the slacked lime that had been previously added. Because of the high pH, the water has a soapy taste and feel. To fix this, carbon dioxide is bubbled through the water which takes the pH of the water down to about 8.0 – 8.4. Other than toning down the pH, this process also helps to improve the taste of the water.
The water then flows into filter houses to get rid of any traces of twigs, sand, germs and small animals. The filter houses use sand filters with different varying particle sizes. The flow of the water through the sand beds is slow to make sure that nothing makes through the filters that is not wanted in the water. After this process, the water now enters underground pipes to complete the water treatment process.
After all these processes, the water is still not safe for home use but it is very close. Just one last step. This is known as chlorination. It is the addition of chlorine gas which is bubbled through the water to kill germs.
After chlorination, the water is safe for use. But, chlorine is only effective for about eight hours at most. To make sure that it stays safe and keeps other germs from re-entering the water during transit, chloramine is added to the water. It is a mixture that contains chlorine and ammonia. This is meant to keep the water safe until you see it trickling out of your tap.
It is a rigorous process with very strict standards and guidelines to make sure that every resident has safe clean and high-quality drinking water.