Wastewater Story| Worksheet Solutions| Class 7

Worksheet solutions for chapter: Wastewater Story for class 7 are provided below.

 

(1) What is wastewater?

Ans-

Water which is rich in lather, mixed with oil, black- brown water that goes down the drains from sinks, showers, toilets, laundries, is known as wastewater.

 

(2) What are the contaminants?

Ans-

Contaminants are suspended impurities dissolved in wastewater or sewage.

 

(3) Why speed of water keep slow in grit and sand tank in wastewater treatment plant?

Ans-

The speed of wastewater keep slow to settle down the sand, grit and pebbles in grit and sand removal tank in wastewater treatment plant.

 

(4) Name the waste which should be thrown in to dustbins?

Ans-

Name of the waste which should be thrown in to dustbin are given below-

(i) Used tealeaves

(ii) Sot toys

(iii)Oil and fat

(iv)Solid food remains

(v)Cotton

(vi)Sanitary towels

 

(5) Why we should not throw chemicals into the drain?

Ans-

We should not throw chemicals (paints, solvents, insecticides, motor oil, medicines) in to the drain because they can kill microbes that help purify water.

 

(6) Fill in the blanks-

(i) Large objects can be removed through ……………….

(ii)……… and ………….. are the use of clean water.

(iii)……….. is wastewater released by homes.

Ans-

(i) Large objects can be removed through bar screens.

(ii)Drinking and bathing are the use of clean water.

(iii)Sewage is wastewater released by homes.

 

(7) Name the organic impurities in the sewage.

Ans-

Name of the organic impurities in the sewage are given below-

(i) Human faeces

(ii) Animal waste

(iii) Oil

(iv)Urea (urine)

 

(8) Write true or false.

(i) World water Day is celebrated on 22nd March.

(ii) Metals are organic impurities find in sewage.

(iii) Aerator is used to pump air in to the clarified water.

Ans-

(i) World water Day is celebrated on 22nd March. True

(ii) Metals are organic impurities find in sewage. False

(iii) Aerator is used to pump air in to the clarified water.  True

 

(9) Write better house keeping practices.

Ans-

Better House Keeping Practices are given below-

(i) Do not throw oil and fats in the drain. They can harden and block the pipes.

(ii) Do not throw fats in open drain because they can clog the pores of soils and can reduce the filtration of water.

(iii)Do not throw chemicals (paints, solvents, insecticides, motor oil, medicines) in to the drain because they can kill microbes that help purify water.

(iv)Always use dustbin to throw used tea leaves, solid food remains, soft toys, cotton, sanitary towels, etc. because these waste can choke the drains. They do not allow free flow of oxygen. It can hamper the degradation process.

 

(10) What is hygienic on – site human waste disposal technology?

Ans-

In Hygienic on-site human waste disposal technology, toilets do not require scavenging. Excreta from the toilets flow through covered drains into a biogas plant.

Helping Topics

Wastewater Story

NCERT Solutions Class 7