3 STAGES OF WASTE WATER TREATMENT - PRIMARY, SECONDARY AND TERTIARY
Water is a crucial part of the survival of almost all the creatures in the world but it gets wasted so often. Now as the world is facing the future crisis of water, it is essential to recycle the sewage water and other dirty water. Sewage Water Treatment Plant is used to purify the contaminated water and makes it reusable.
Depending upon the degree of contamination, Sewage Water Treatment Plant works in stages. This water contains phosphorous, nitrogen, solids and bacteria which get removed in different processes. The sewage water is processed through the chemical, physical and biological procedure for the cleaning purpose. Passing through all the processes, semi-solid slurry gets produced at the end of the sewage water treatment plant. Further with chemical processes, this slurry is made suitable for the land.
Let us discuss the three stages of Sewage Water Treatment Plant:
In this stage of sewage water treatment plant, wastewater is stored in a large tank for a while. By this, solids get separated; heavier stuck to the bottom and lighter solids tend to float at the surface. This way, contaminants get filtered and the remaining liquid is directed to the more rigorous secondary stage. These specifically designed tanks used in the primary phase have consisted of mechanical scrappers, which keep shifting the sludge in other vessels with hopper.
The design of secondary treatment is the degradation of biological contaminants. They are substantially removed from the sewage water by following aerobic methods:
In this method, a variety of filters is used for the process such as sand filters, contact filters, and trickling filters. Water is passed through these filters to separate the additional sediments from the wastewater.
It is a time-taking process which involves the introduction of air in wastewater in order to enhance oxygen saturation. This process effectively contributes to the filtering of biological waste from sewage water. Approx 30 hours of time is required for the powerful result.
This method is generally used in warmer weather. It involves the natural bodies like lagoons which permit wastewater to pass and being retained for three to four weeks.
Tertiary is the final stage of the sewage water treatment plant. Sometimes, the water coming from the secondary stage is not sufficiently clean. In such cases, the water has to go through this final process before getting discharged for use. In this treatment phosphorous and ammonia filled nitrogen contaminants are reduced from the water. To reduce phosphorus, a dosing system is applied and for ammonia filled nitrogen removal, nitrifying and denitrifying processes are used. In this method, this ammonia-nitrogen gets transformed in nitrogen gas which gets evaporated to the environment. Thus sewage water gets completely clean and ready for further uses.
With the help of sewage water treatment plant, a continuous supply of water in the world can be maintained for the ages. This kind of plant is very effective for domestic wastewater and industrial wastewater both.
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