When the faucet is opened, clean tasty water goes out. It goes through different purification steps before flowing from taps.
Drinking water consists of water molecules, as well as a wide range of substances. It has different properties, one of which is it can easily dissolve other substances. Whenever it rains, water that falls to the ground dissolves particles, substances and gases like oxygen, which is present in the atmosphere. Rain water also dissolves the contaminants seen in the air. Surface water that flows on the ground dissolves many different substances – like microorganisms, minerals, organic matter and sand particles. When it settles in the ground, it becomes groundwater. Here it comes in contact with rocks and soil, causing it to have large amounts of dissolved minerals. Agricultural and industrial waste, as well as sewer discharge are human activities that enable pollutants to enter the water.
The Capacity to Clean Itself
Water has the ability to clean itself. During biological processes, contaminants are removed from the water. The moment water settles into the ground, ground layers bring about the occurrence of filtration. Contaminants are either broken down, or left on the ground layer. However, the self-cleaning ability of water is not sufficient to generate clean water for drinking. This is due to the agricultural and industrial contaminants that have entered and accumulated in the surface and groundwater for several decades. During the ’70s, industrial and waste water discharges were discovered to cause water contamination. Right after this was discovered, measures were taken to avoid water pollution. Before waste water can be discharged, it should conform to legal standards. This can only happen if water is purified.
In spite of all the measures being followed, water still needs to be treated at times before it can be safe to drink.
During the water purification process, waste water is treated so it can be potable water, which conforms to the legal standards in terms of their physical, chemical and bacteriological aspect. This means it has no flavor or odor, it is bright, and lastly, it is chemically stable or non-corrosive.
The basics of surface water treatment process include the following stages:
At this stage, chemicals such as alum are incorporated into the water. Suspended particles stick to the chemicals to come up with “floc”.
When particles are stuck, they add too much weight and drop to the lowermost part of the chamber. This is the stage when most of them get stuck and form into sediments going down to the surface below. Then the water goes on to the chamber.
While water passes through the chamber, the finer particles or sediments are filtered above layers of gravel, sand and charcoal.
To eliminate other living organisms like bacteria that may be present in water, chlorine and other disinfection methods are used. It is just normal and regular for water to have living organisms. The water goes into big storage tanks and remains there to finish the process of disinfection. At the end part of the storage tanks, huge pipes are joined together so that water can be transported to homes and offices.