Water purification plays a key role in ensuring that we have safe, germ free drinking water each day. We take this for granted without knowing the facts and steps taken in order for us to obtain this. If it wasn’t for this system created, millions would be faced with the possibility of getting water borne diseases, which could result in death. According to wateraid, one in eight human beings around the world, mostly in the developing word, go without clean, drinkable water every day. To top this, every 20 seconds, one child dies from diarrhea caused by contaminated water and poor sanitation. In wealthier countries like the UK, this is less common due to the system which will be talked about in this article.
Water, often from lakes and rivers, are taken in by large pumps into the purification plant. These pumps contain screens that exclude organisms, weeds, branches and other debris. However, these screens may not be required for groundwater due to these objects and organisms not being likely to found in the water. The purification plant may aerate the water to increase the oxygen content, helping remove nasty odors and tastes within the water.
Coagulation and Flocculation
This step of the process helps clear water of small particles in the water that cause it to look cloudy and turbid. Turbidity renders the water hard to disinfect. This helps remove coagulant chemicals throughout it. The small particles, including many bacteria, begin to form large clumps called flocs or floccules. In flocculation, the water is mixed and stirred gently so that these clumps combine and precipitate out further.
The water and flocs are pumped into sedimentation basins. In this stage, the flocs settle beneath the water so that they can be removed. About 90% of the suspended particles responsible for turbidity are removed at this point, so the water is almost certain to not become turbid. Furthermore, large amounts of bacteria are removed in this stage.
In filtration, the water flows through a multilayer medium such as sand, activated carbon or anthracite coal. This helps remove 99.5% of the solid materials remaining it, whether flocs, microbes or minerals. This step usually is the last one in the process of removing solid substances from the water.
This stage kills of disease bearing organisms in the water, This is done using chlorine compounds as disinfectants. Although chlorine is still one of the most common disinfectants, ultraviolet radiation and ozone gas becoming more widespread. Chlorine is increasing in cost and have health effects on humans and fish. In addition, some disease-carrying microbes resist chlorine.
Corrosion and Scale Control
The pH of the water is adjusted so that it neither corrodes nor deposits too much scale in pipes. Small quantities help pipes function but excess quantities disrupt plumbing systems. However, no amount of corrosion in the water distribution system is desirable. Corrosion of pipes release leads and copper which are poisonous.
Taste and Odor Control
The final stage of the process is to add chemicals, ozonation or filtration in order to remove tastes and odors. At this stage, some municipalities also require the addition of fluoride to the water for dental health.
This process is very important but it is undermined, not thought of highly, it is a complex process and is important for health. In areas where there are poor sanitary conditions, it is important that water is placed through a process similar to this, to reduce the number of diseases caused through poor water hygiene.