Class 7 Science Worksheet for Wastewater Story with Answers

Class 7 Science Worksheet for Wastewater Story worksheet will help you learn about the journey of wastewater from our homes and industries to its treatment and safe release back into nature. Understanding how wastewater is managed is important for keeping our environment clean and ensuring we have clean water to use.

In this Class 7 science wastewater worksheet, you will explore different questions and activities that explain the steps involved in treating wastewater. You will learn about the materials found in wastewater, how it is cleaned, and why sanitation is essential. By the end of this worksheet, you will have a better understanding of how we can protect our water resources and keep our communities healthy.

The Wastewater Story is an important part of our everyday lives. It begins when we use water in our homes, schools, and industries. This used water, which contains various impurities, becomes wastewater. 

Through a series of treatment processes, this wastewater is cleaned and treated to remove harmful substances. The cleaned water is then released back into rivers, lakes, or the ground, where it can be safely reused by nature and people. This story helps us understand the importance of treating wastewater and how it helps maintain a healthy environment. Let's start this exciting journey into the world of wastewater.

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Class 7 Science Worksheet for Wastewater Story: Short Answer Questions

Ques 1: What is the function of bar screens in a wastewater treatment plant?

Ans: Bar screens remove large objects such as rags, sticks, cans, plastic packets, and napkins.

Ques 2: What is sewage?

Ans: Sewage is wastewater that contains dissolved and suspended solid impurities.

Ques 3: Why should oils and fats not be thrown into drains?

Ans: Oils and fats can harden and block pipes. In open drains, fats clog the soil pores, reducing its effectiveness in filtering water.

Ques 4: What is a wastewater treatment plant?

Ans: A wastewater treatment plant is a facility designed to remove impurities from sewage and properly treat contaminants and clarified water.

Ques 5: What are alternative arrangements for sewage disposal?

Ans: Septic tanks, chemical tanks, and compost pits can serve as alternative arrangements for sewage disposal.

Ques 6: Why is discharging untreated sewage into water bodies harmful?

Ans: Untreated sewage contains disease-causing microorganisms and pollutants that can contaminate soil and water, causing various diseases.

Ques 7: What is clarified water?

Ans: Clarified water is water that has been treated to remove impurities (contaminants).

Ques 8: What is a septic tank?

Ans: A septic tank is a small sewage treatment system with an anaerobic bacterial environment that decomposes waste matter.

Also Check: NCERT Solutions for Class 7 Science Wastewater Story

Class 7 Science Worksheet for Wastewater Story: Multiple Choice Questions

Ques 1: Which chemical is used to disinfect water?

(a) Chlorine

(b) Washing soda

(c) Silica

(d) Coal

Ans: (a) Chlorine

Ques 2: Sewage is primarily:

(a) liquid waste.

(b) solid waste.

(c) gaseous waste.

(d) a mixture of solid and gas

Ans: (a) liquid waste.

Ques 3: Open drain systems are breeding grounds for which of the following?

(a) Flies

(b) Mosquitoes

(c) Disease-causing organisms

(d) All of these

Ans: (d) All of these

Ques 4: Which of the following is not a source of wastewater?

(a) Sewers

(b) Homes

(c) Industries

(d) Hospitals

Ans: (a) Sewers

Class 7 Science Worksheet for Wastewater Story: Long Answer Type Questions

Ques 1: Describe the issues related to open defecation.

Ans: Many people in our country defecate in the open due to a lack of proper sewerage facilities. This practice poses significant health risks, leading to the spread of diseases like cholera, typhoid, hepatitis-A, polio, and diarrhea. Each year, about 100,000 children in India die from diseases caused by fecal contamination. It is crucial to stop this practice by providing adequate facilities to every citizen.

Ques 2: What measures can you take at home to ensure the efficient functioning of the sewerage system?

Ans:

• Avoid disposing of oils and fats in the drain.
• Refrain from pouring chemicals like paints, medicines, grease, and insecticides into the drain.
• Do not throw solid wastes like food remains, tea leaves, cotton, and plastic bags into the drain.
• Conserve water.
• Use phosphate-free soaps and detergents.
• Do not use the toilet as a wastebasket.

Fill in the Blanks

Ques 1: The materials present in wastewater are called _________.

Ans: contaminants

Ques 2: Water is used as a coolant in the _________.

Ans: nuclear plant

Ques 3: A septic tank is suitable for areas with _________.

Ans: sandy soil

Ques 4: _________ are the main contributors to water pollution.

Ans: Industries

Ques 5: In an aerated tank, _________ is broken down.

Ans: organic matter

Ques 6: The main sewer pipelines are called _________.

Ans: sewage

Ques 7: Aerobic bacteria feed on organic matter and produce _________.

Ans: biogas

Ques 8: The junction of home sewers is called a _________.

Ans: manhole

Ques 9: Microorganisms that aid in wastewater treatment settle at the bottom of the tank to form _________.

Ans: activated sludge

Ques 10: The sludge from the settlement tank is transferred to another tank called _________.

Ans: digester

Ques 11: Large objects and garbage in wastewater are removed by passing through the _________.

Ans: bar screen

Ques 12: In the final step, the wastewater is treated with _________.

Ans: chlorine

Ques 13: The activity of bacteria on sludge causes _________.

Ans: decomposition

Ques 14: Wastewater treatment primarily involves the removal of _________.

Ans: contaminants

Class 7 Science Worksheet for Wastewater Story: True/False

Ques 1: Sludge is used as an insecticide.

Ans: False. Sludge is used as fertilizer.

Ques 2: Disinfection is the last step of wastewater treatment.

Ans: True.

Ques 3: Open drains can trigger malaria.

Ans: True.

Ques 4: Biological treatment is also called secondary treatment.

Ans: True.

Class 7 Science Worksheet for Wastewater Story: Additional Questions

Ques 1: What is wastewater? Can it be recycled?

Ans: Wastewater is water that has been used and contains waste materials. Yes, it can be recycled after proper treatment.

Ques 2: What are the sources of wastewater?

Ans: Sources of wastewater include homes, industries, hospitals, and commercial organizations.

Ques 3: What is activated sludge?

Ans: Activated sludge is a mixture of bacteria and particles used in the treatment of wastewater.

Ques 4: Name a chemical used to further treat clarified water.

Ans: Chlorine.

Ques 5: Explain the importance of good sanitation practices.

Ans: Good sanitation practices, such as proper waste disposal and maintaining clean surroundings, help prevent the spread of diseases and promote overall health and hygiene.

Ques 6: What is the purpose of bubbling air into the aeration tank during sewage treatment?

Ans: Bubbling air into the aeration tank provides oxygen to aerobic bacteria, which helps in the decomposition of organic matter.

Ques 7: What are the floating impurities in sewage? How are they removed?

Ans: Floating impurities in sewage include oil, grease, and plastic. They are removed using skimmers and bar screens.

CBSE Class 7 Science Worksheet for Wastewater Story

Ques 1: The kinds of material present in the wastewater are called:

Ans: contaminants

Ques 2: Water is used as a coolant in the:

Ans: nuclear plant

Ques 3: A septic tank is suitable for areas with:

Ans: sandy soil

Ques 4: The main contributors to water pollution are:

Ans: industries

Ques 5: In an aerated tank, _________ is broken down:

Ans: organic matter

Ques 6: The main sewer pipelines are called:

Ans: sewage

Ques 7: Aerobic bacteria feed on organic matter and produce:

Ans: biogas

Ques 8: The junction of home sewers is called 

Ans: manhole

Ques 9: Microorganisms that aid in wastewater treatment settle at the bottom of the tank to form:

Ans: activated sludge

Ques 10: The sludge from the settlement tank is transferred to another tank called:

Ans: digester

Ques 11: Large objects and garbage in wastewater are removed by passing through the:

Ans: bar screen

Ques 12: In the final step, the wastewater is treated with:

Ans: chlorine

Ques 13: The activity of bacteria on sludge causes:

Ans: decomposition

Ques 14: Wastewater treatment primarily involves the removal of:

Ans: contaminants