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प्रश्न
What is water recycling? Explain the conventional wastewater recycling treatment methods.
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उत्तर
Water recycling is reusing treated wastewater for beneficial purposes such as agricultural and landscape irrigation, industrial processes, flushing in toilets, and groundwater recharge. Conventional wastewater treatment consists of a combination of physical, chemical, and biological processes which remove solids, organic matter, and nutrients from wastewater.
The wastewater treatment involves the following stages:
- Primary treatment: Primary treatment involves the temporary holding of the wastewater in a tank. The heavy solids get settled at the bottom while oil, grease and lighter solids float over the surface. The settled and floating materials are removed. The remaining liquid may be sent for secondary treatment.
- Secondary treatment: Secondary treatment is used to remove the biodegradable dissolved organic matter. This is performed in the presence of oxygen by aerobic microorganisms (Biological oxidation). The microorganisms must be separated from treated wastewater by sedimentation. After separating the sediments of biological solids, the remaining liquid is discharged for tertiary treatment.
- Tertiary treatment: Tertiary or advanced treatment is the final step of sewage treatment. It involves the removal of inorganic constituents such as nitrogen, phosphorus, and microorganisms. The fine colloidal particles in the sewage water are precipitated by adding chemical coagulants like alum or ferric sulfate.

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संबंधित प्रश्न
Colour the given picture and write the correct name in the given blanks.
(Precipitation, Evaporation, Condensation, Water storage)

Which of the following is not a part of water cycle?
Water present in rivers, lakes, and ponds is unfit for use by human beings.
Maximum surface water is stored in lakes.
Transpiration takes place in rivers and lakes.
One of the following processes is not a step involved in the water-cycle operating in nature
The term “water-pollution” can be defined in several ways. Which of the following statements does not give the correct definition?
Which of the following inhibits the seepage of rainwater into ground?
Fill in the blanks in the given passage.
The rainwater and ______ from other sources such as rivers and ponds seeps through the ______ and fills the empty spaces and cracks deep below the ground. The process of seeping of water into the ground is called ______.
Place the following statements in a proper order to form a meaningful paragraph.
- Which in turn decreases the seepage of rain water into the ground.
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- This results in depletion of water table and creates scarcity of more water.
