Saturday, January 26, 2013

NCERT/CBSE -7th Science Ch–Waste Water Story Solved Questions

Q. Explain the process of waste water treatment?

Ans: The wastewater is treated through physical, chemical, and biological processes to remove the physical, chemical and biological contaminants.
Physical - separates the large waste
Biological- Adding of microorganisms to digest waste and produce oxygen in water
Chemical- Chlorine and other chemicals are added into the water to finally purify it.

Q. what is sewage?

Ans: Wastewater is generated during various activities in homes, industries, hospitals, offices, and laundry services etc. This waste water is called sewage.

Q. Explain the vercomposting toilet ?           

Ans: Vermicomposting toilets are those which do not use water and are very environment friendly. They can be utilized in areas where water is a scarcity and can also be used in forests and other areas where sewage lines have not been built. This process uses worms for decomposition of waste. The waste is degraded in a container.
Q. what are the process of waste water management of rain water ?

Ans: The rain water that runs down after washing off the rooftops, roads etc. is dirty and carries harmful pollutants. The waste water containing solid and liquid pollutants is known as sewage. The process of removing the contaminants from sewage water is done through various stages. This entire process is known as the sewage water treatment process.

Q. What is Eutrophication?

Ans: Eutrophication is the presence of excess nutrients in water bodies. Release of nutrient rich sewage and industrial effluents lead to introduction of nutrients such as nitrogen and phosphorus in the water body. This leads to the increase in temperature called algal blooms.

Q. Each tree can make its own manure. How?

Ans: Plants shade their leaves that are biodegrable and converted into compost when get covered under soil. Thus each tree can make its own manure.

Q. Fill in the blanks:

(a) Cleaning of water is a process of removing  pollutants.
(b) Wastewater released by houses is called   sewage.
(c) Dried sludge is used as manure.
(d) Drains get blocked solid and liqidby tealeaves, solid food remains, soft toys, cotton, and  sanitary towels .
CBSE 7th Waste Water Story management Solved Test Paper  Click here
CBSE 7th Waste Water Story management Solved questions    Click here        
Assignment Chapter –Waste Water Story                                   Click Here

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