SELECT * FROM question_mgmt as q WHERE id=6148 AND status=1 SELECT id,question_no,question,chapter FROM question_mgmt as q WHERE courseId=11 AND subId=16 AND chapterId=478 and ex_no='1' AND status=1 ORDER BY CAST(question_no AS UNSIGNED) CBSE Free NCERT Solution of 7th science Wastewater Story name two chemicals used to disinfect water

Question:

Name two chemicals used to disinfect water.

Answer:

It may be necessary to disinfect the treated water with chemicals like chlorine or ozone before releasing it into the distribution system. The purpose of disinfection in the treatment of wastewater is to eliminate completely the harmful micro- organisms in the water to be discharged back into the environment. The treated wastewater can also be passed through layers of sand (called sand filters). Sand filtration removes most of the remaining suspended matter from the treated wastewater. It has been suggested that we should plant Eucalyptus trees all along the sewage ponds. This is because eucalyptus trees absorb all the surplus
wastewater from the sewage ponds rapidly and release pure water vapour into the atmosphere (through transpiration).


SELECT ex_no,question,question_no,id,chapter FROM question_mgmt as q WHERE courseId='11' AND subId='16' AND ex_no!=0 AND status=1 and id!=6148 ORDER BY views desc, last_viewed_on desc limit 0,10
SELECT ex_no,question,question_no,id,chapter FROM question_mgmt as q WHERE courseId='11' AND subId='16' AND ex_no!=0 AND status=1 and id!=6148 ORDER BY last_viewed_on desc limit 0,10

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  • 4 months ago

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  • Answered by Ekta Mehta
  • 4 months ago

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  • Answered by Ekta Mehta
  • 4 months ago

Taking Screenshots on your Samsung Galaxy M31s is very easy and quick.


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