Wastewater Story is Chapter 18 taken from the JKBOSE textbook of Science for students of Class 7th. In the previous post, I provided you with Questions and Answers for Chapter 17 Forests Our Lifeline. This post is about Wastewater Story Class 7 Question Answers. Before we proceed to Question Answers, you need to have basic information about the chapter. So here is a brief overview of the chapter:
Wastewater Story Class 7 Question Answers
Overview of Chapter
- WATER, OUR LIFELINE.
- WHAT IS SEWAGE?
- WATER FRESHENS UP — AN EVENTFUL JOURNEY.
- WASTEWATER TREATMENT PLANT. (WWTP)
- BETTER HOUSEKEEPING PRACTICES.
- SANITATION AND DISEASE.
- ALTERNATIVE ARRANGEMENT FOR SEWAGE DISPOSAL.
- SANITATION AT PUBLIC PLACES.
Water which is Rich in leather, mixed with oil, black–brown water that goes down the drains from sinks, showers, toilets, and laundries is dirty. It is called wastewater. This used water should not be wasted. We must clean it up by removing pollutants.
WATER, OUR LIFELINE: Clean water is a basic need of human beings. Clean water that is fit for use is unfortunately not available to all. It has been reported that more than one billion of our fellow human beings have no access to safe drinking water.
The water which is unfit for human consumption becomes the source of many water-borne diseases which ultimately lead to the loss of human life. The water is cleaned by removing pollutants before it enters a water body or is used. The process of wastewater treatment is commonly known as sewage treatment.
WHAT IS SEWAGE? Sewage is wastewater released by homes, industries, hospitals, offices and other users. It also includes rainwater that has run down the street during a storm or heavy rain. The water that washes off roads and rooftops carries harmful substances with it. Sewage is liquid waste. Sewage is composed of organic, and inorganic impurities, nutrients, bacteria and other microbes.
WATER FRESHENS UP — AN EVENTFUL JOURNEY: In a home or a public building generally, one set of pipes brings clean water and another set of pipes takes away wastewater. For proper sanitation, a well-maintained sewage system is required.
Sewerage is an underground network of interconnected pipes that transports or carries the sewage from the place where it is produced to the sewage treatment plants where it is processed.
WASTEWATER TREATMENT PLANT: A place where wastewater or sewage from houses and other buildings is brought for processing is called a wastewater treatment plant. Treatment of wastewater involves physical, chemical, and biological processes, which remove physical, chemical and biological matter that contaminates the wastewater.
BETTER HOUSE-KEEPING PRACTICES: We can minimise and manage waste at our houses in the following manner:
- Avoid throwing fats and oils down the drain because it can harden and block the pipes.
- Used tea leaves, solid food remains, soft toys, polythene bags, cotton etc should not be thrown down the drain.
- The chemicals like paints, insecticides, solvents medicines and motor oils should not be thrown in drains as they kill helpful microbes.
SANITATION AND DISEASE: Poor sanitation and contaminated drinking water is the cause of a large number of diseases and infections. Untreated human excreta is a health hazard. It may cause water pollution and soil pollution. Both the surface water and groundwater get polluted. Contaminated water can spread many water-borne diseases like cholera, typhoid, polio, meningitis, hepatitis and dysentery etc.
ALTERNATIVE ARRANGEMENT FOR SEWAGE DISPOSAL: Low-cost onsite sewage disposal systems are being encouraged. Examples are septic tanks, chemical toilets, and composting pits.
SANITATION AT PUBLIC PLACES: In our country fairs are organised periodically. A large number of people participate in them. In the same way railway stations, bus depots, airports, and hospitals are very busy places. Thousands of people visit them daily. A large amount of waste is generated here. All of us can contribute to maintaining sanitation in public places. We should not scatter litter anywhere. If there is no dustbin in sight, we should carry the litter home and throw it in the dustbin.
Chapter 18 Wastewater Story Questions
- 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 by cooking oils and fats.
2. What is sewage? Explain why it is harmful to discharge untreated sewage into rivers or seas.
Ans. Sewage is wastewater released by homes, industries, hospitals, offices and other users. It also includes rainwater that has run down the street during a storm or heavy rain. The water that washes off roads and rooftops carries harmful substances with it. Sewage is liquid waste.
It is harmful to discharge untreated sewage into rivers or seas because it can contaminate the source of water. This water becomes unfit for marine life also if this water is used for human consumption like drinking, it can cause diseases like cholera, diarrhoea, dysentery, typhoid etc.
3. Why should oils and fats be not released in the drain? Explain.
Ans. Oils and fats should not be released in drains because they harden and blocks the pipes and do not allow the water to flow. In open drains, oil and fats clog the soil pores and reduce their capacity to filter water.
4. Describe the steps involved in getting clarified water from wastewater.
Ans. Treatment of wastewater involves physical, chemical, and biological processes, which remove physical, chemical and biological matter that contaminates the wastewater. The steps involved in getting clarified water from wastewater are as follows:
1. Bar Screens: Passing wastewater through bar screens can remove large objects like rags, sticks, cans, plastic packets, napkins etc.
2. Grit and Sand Removal Tank: Wastewater is then taken to a grit and sand removal tank. The speed of incoming wastewater is decreased to allow sand, grit and pebbles to settle down.
3. Sludge: The water is then allowed to settle in a large tank which is sloped towards the middle. Solid-like faeces settle at the bottom and are removed with a scraper called sludge.
4. Decomposition by Anaerobic Bacteria: The sludge is then transferred to a separate tank where it is decomposed by anaerobic bacteria to produce biogas which is used as fuel.
5. Aerator: Air is pumped into the clarified water to help aerobic bacteria to grow. Bacteria consume human waste, food waste, soaps and other unwanted matter still remaining in clarified water. After several hours, the suspended microbes settle at the bottom of the tank as activated sludge. The water is then removed from the top.
5. What is sludge? Explain how it is treated.
Ans. It is a solid faecal matter collected from the wastewater after passing through screen bars and a grit and sand removal tank.
Treatment of Sludge: The sludge is removed by scraper and then transferred to a tank where it is decomposed by anaerobic bacteria to produce biogas. It is used as fuel. Dried sludge is used as manure.
6. Untreated human excreta is a health hazard. Explain.
Ans. Untreated human excreta is a health hazard. It may cause water pollution and soil pollution. Both the surface water and groundwater get polluted. Contaminated water can spread many water-borne diseases like cholera, typhoid, polio, meningitis, hepatitis and dysentery etc.
7. Name two chemicals used to disinfect water.
Ans. Chlorine and Ozone are the two chemicals which are used to disinfect water.
8. Explain the function of bar screens in a wastewater treatment plant.
Ans. In wastewater treatment plants, bar screens are used to remove physically large-sized waste objects like plastic packets, napkins, rags, cans, and sticks from the water.
9. Explain the relationship between sanitation and disease.
Ans. Sanitation and disease are related to each other. Poor sanitation and contaminated drinking water are the cause of a large number of diseases. Untreated human excreta is a health hazard. It may cause water pollution and soil pollution. The contaminated water when used for drinking can cause diseases such as cholera, typhoid, dysentery, hepatitis etc. Thus, we can say that sanitation and disease are related to each other.
10. Outline your role as an active citizen in relation to sanitation.
Ans. We as active citizens have an important role to play in proper sanitation. Some of the important points we should follow are:
1. We should approach higher authorities to cover all the open drains.
2. Do not allow litter to be thrown here and there and keep the city clean.
3. Provide dustbins in proper places.
4. We should make people aware of hygiene and sanitation.
- Here is a crossword puzzle: Good luck!
- Liquid waste products
- Solid waste extracted in sewage treatment
- A word related to hygiene
- The waste matter discharged from the human body
- Used water
- A pipe carrying sewage
- Micro-organisms which cause cholera
- A chemical to disinfect water
- Study the following statements about ozone:
(a) It is essential for breathing of living organisms.
(b) It is used to disinfect water.
(c) It absorbs ultraviolet rays.
(d) Its proportion in air is about 3%.
Which of these statements are correct?
(i) (a), (b) and (c)
(ii) (b) and (c)
(iii) (a) and (d)
(iv) All four
Ans. (ii) (b) and (c)
- Tick mark (ü) the correct answers.
- The disease caused by polluted water
(d) All of these
Ans. (d) All of these
- Malaria can be triggered by
(a) Open drains
(b) Closed drains
(d) Pipe lines
Ans. (a) Open drains
- Waste that can be broken down by bacteria
Ans. (c) Biodegradable
- Stage of wastewater treatment for removing large particles
Ans. (c) Primary
That’s all about Wastewater Story Class 7 Question Answers. Hope it has helped you. Do share your views about this post in the comment section below.
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