Table of Contents
Wastewater Story Class 7 MCQ
CBSE Class 7 Science Wastewater Story MCQ With Answers
Q1. Which component of wastewater is broken down by bacteria in a treatment plant?
A. Oil
B. Soap
C. Organic waste
D. Sand
Answer: C. Organic waste
Q2. What is the first step in the wastewater treatment process?
A. Disinfection
B. Sludge removal
C. Screening
D. Aeration
Answer: C. Screening
Q3. What is the term for solid waste that settles at the bottom of a treatment tank?
A. Slime
B. Sludge
C. Sediment
D. Filtrate
Answer: B. Sludge
Q4. Which gas is commonly produced during sludge digestion?
A. Oxygen
B. Hydrogen
C. Biogas
D. Ammonia
Answer: C. Biogas
Also Check: NCERT Solutions for Class 7 Science Chapter 18
Q5. What does sewage mainly consist of?
A. Saltwater and chemicals
B. Wastewater and human excreta
C. Only chemicals
D. Only industrial waste
Answer: B. Wastewater and human excreta
Q6. Why is aeration important in wastewater treatment?
A. To add chlorine
B. To kill bacteria
C. To help bacteria break down waste
D. To remove color
Answer: C. To help bacteria break down waste
Q7. What does a bar screen in a treatment plant do?
A. Disinfect water
B. Kill germs
C. Filter out large objects
D. Mix water
Answer: C. Filter out large objects
Q8. Which one of these is a natural method of water purification?
A. Chlorination
B. Boiling
C. Filtration through sand and soil
D. Adding bleach
Answer: C. Filtration through sand and soil
Q9. What is the full form of WWTP?
A. Water Waste Treatment Process
B. Wastewater Treatment Plant
C. Water Washing and Treatment Plant
D. Water Waste Transfer Protocol
Answer: B. Wastewater Treatment Plant
Q10. Which process involves adding air to wastewater?
A. Disinfection
B. Sedimentation
C. Aeration
D. Screening
Answer: C. Aeration
Also Check: NCERT Class 7 Notes Science Chapter 18
Q11. Pathogens in sewage are mainly:
A. Stones
B. Harmful bacteria and viruses
C. Plastic items
D. Detergents
Answer: B. Harmful bacteria and viruses
Q12. Which part of the sewage treatment involves removing oil and grease?
A. Primary treatment
B. Secondary treatment
C. Screening
D. Skimming
Answer: D. Skimming
Q13. What is the role of earthworms in natural wastewater treatment?
A. They release chlorine
B. They absorb water
C. They help break down waste
D. They kill germs
Answer: C. They help break down waste
Q14. Vermi-processing toilets use:
A. Machines
B. Sand filters
C. Earthworms
D. Detergents
Answer: C. Earthworms
Q15. Treated water from WWTP is:
A. Ready for drinking
B. Released into rivers
C. Used for cooking
D. Stored underground
Answer: B. Released into rivers
Also Check: NCERT Exemplar Solutions for Class 7 chapter 18
Q16. One harmful effect of untreated sewage is:
A. Increase in rainfall
B. Decrease in water temperature
C. Water pollution
D. Water purification
Answer: C. Water pollution
Q17. Which one is not a source of wastewater?
A. Toilets
B. Washing machines
C. Trees
D. Factories
Answer: C. Trees
Q18. Which stage of sewage treatment uses microbes to decompose organic matter?
A. Screening
B. Primary treatment
C. Secondary treatment
D. Disinfection
Answer: C. Secondary treatment
Q19. Which system uses bacteria to clean water naturally?
A. Chemical disinfection
B. Septic tanks
C. Water harvesting
D. Solar purification
Answer: B. Septic tanks
Q20. Biogas is mainly composed of:
A. Carbon dioxide
B. Oxygen
C. Methane
D. Hydrogen
Answer: C. Methane
Q21. Which method removes suspended solids in a WWTP?
A. Boiling
B. Sedimentation
C. Chlorination
D. Distillation
Answer: B. Sedimentation
Q22. Which one is a cleaner practice to avoid water pollution?
A. Flushing oils in toilets
B. Throwing garbage in drains
C. Using eco-friendly soaps
D. Dumping industrial waste in rivers
Answer: C. Using eco-friendly soaps
Q23. Which activity generates the most household wastewater?
A. Sweeping
B. Watering plants
C. Bathing and washing
D. Reading
Answer: C. Bathing and washing
Q24. Treated sludge is often used as:
A. Fuel
B. Fertilizer
C. Plastic
D. Glass
Answer: B. Fertilizer
Q25. Which of the following helps control bad smell in wastewater?
A. Bleaching powder
B. Vinegar
C. Salt
D. Sugar
Answer: A. Bleaching powder
Q26. Water in a treatment plant is disinfected mainly by:
A. Sand
B. Bacteria
C. Chlorine
D. Sugar
Answer: C. Chlorine
Q27. A simple method to prevent drain clogging is:
A. Pouring boiling water
B. Avoid throwing waste in sinks
C. Adding detergent daily
D. Using acid
Answer: B. Avoid throwing waste in sinks
Q28. What is the main goal of wastewater treatment?
A. Increase its color
B. Add nutrients
C. Make water reusable and safe
D. Remove its smell only
Answer: C. Make water reusable and safe
Q29. The main function of a septic tank is:
A. Heating water
B. Purifying air
C. Treating household sewage
D. Mixing oil
Answer: C. Treating household sewage
Q30. Which disease can spread due to untreated wastewater?
A. Flu
B. Malaria
C. Typhoid
D. Asthma
Answer: C. Typhoid
Benefits of Practicing Wastewater Story Class 7 MCQs with Answers
- Makes Learning Easier and More Fun
MCQs turn boring theory into fun quizzes! They help students grasp tricky topics like sewage treatment and clean water processes in a playful and engaging way. - Sharpens Thinking and Recall Skills
Regular MCQ practice trains the brain to think fast and recall details like how wastewater is treated, what sludge is, and why sanitation is important. - Saves Time During Revision
Instead of re-reading the whole textbook, MCQs give a smart and speedy way to review all key points from the Wastewater Story chapter—perfect for last-minute prep! - Improves Exam Confidence
Solving Class 7 Science MCQs helps students get familiar with the question pattern, boosting their confidence to handle actual exam questions with ease. - Matches the CBSE Pattern Perfectly
These questions follow the CBSE Class 7 syllabus and are aligned with NCERT solutions for Class 7 Science, making sure students are always on the right track with their preparation.
