is it possible for river water to get clean naturally by the processes that are similar to those adopted in a waste water treatment plant? if so how
Please find below the solution to the asked query
Yes, river water is treated in a similar way as those adopted in a waste water treatment plant for the supply to homes. It can be cleaned up using the following steps:
- Bar screen
- Sand and grit removal
- Clarification
- Aeration
Bar screen
The purpose of this section of the water treatment plant is to remove large-sized objects from the such as rags, sticks, cans, plastic packets, napkins, papers etc by allowing the water to pass through a bar screen.
Grit and sand removal
After the water is treated through the bar screen, it goes into the grit and sand removal tank. In this tank, the flow of the water is slowed down to allow sand, pebbles, and grit to settle down at the bottom of the tank.
Clarification
After the water passes through the grit and sand removal tank, it is allowed to settle down in a large tank, with a slope toward the middle. Solid materials settle at the bottom and are removed with the help of a scraper. The deposited waste material thus collected is called sludge. The contaminants that float over the surface of the water are removed by a skimmer. The water that is treated in this process is called clarified water and the process is called clarification.
Sludge in the tank is allowed to decompose with the help of anaerobic bacteria (bacteria which can survive in the absence of oxygen) to produce biogas, that can be used for the generation of electricity.
Aeration
Aeration is the process that follows the process of clarification. Air is pumped into the water so that the aerobic bacteria (bacteria which need oxygen to survive), can grow in it. These bacteria consume human wastes, food wastes, soaps and other pollutants that remain in the clarified water.
This pumping of air into the clarified water goes on for several hours. Eventually, the microbes start to settle down at the bottom of the tank as activated sludge. The process of removal of water starts from the top of the tank. The activated sludge that settles down at the bottom of the tank is about 97% water. This water is removed by machines or sand-drying beds. Dry sludge can be used as manure. The water treated through this process contains low organic material. It is therefore discharged into the sea or river or into the ground for natural purification.
Before releasing the water treated in this manner, chlorination is necessary in order to make it germ-free. Chlorine tablets are thus added to it. This process is known as chlorination . Chlorine acts as a disinfectant. It is harmless to humans and other animals.
Hope this information will clear your doubts about the topic.
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