MCQ on Environmental Sanitation and Sanitary Engineering

🟢 Easy Level (1–20)

1. Which of the following is the main aim of environmental sanitation?
   a) Population growth
   b) Industrial development
   c) Urban beautification
   d) Disease prevention ✔️
   Explanation: Environmental sanitation helps reduce disease transmission through clean environments.
2. Which method is commonly used for the purification of drinking water?
   a) Filtration ✔️
   b) Combustion
   c) Irradiation
   d) Sedimentation
   Explanation: Filtration removes impurities and pathogens from water effectively.
3. Which is the best method to dispose of human excreta in rural areas?
   a) Open dumping
   b) Pit latrine
   c) Composting toilet ✔️
   d) River disposal
   Explanation: Composting toilets are eco-friendly and suitable for rural sanitation.
4. The term “sanitation barrier” refers to:
   a) Interruption of disease transmission ✔️
   b) A wall built for privacy
   c) A type of disinfectant
   d) A type of drainage system
   Explanation: Sanitation barriers break the cycle of disease transmission.
5. Which of the following is considered a safe water source?
   a) Open pond
   b) Uncovered well
   c) Protected spring ✔️
   d) River water
   Explanation: Protected springs are shielded from contamination.
6. Sanitary engineering deals with:
   a) Structural designs only
   b) Water supply and waste management ✔️
   c) Road construction
   d) Industrial layout
   Explanation: Sanitary engineering focuses on clean water supply and waste disposal.
7. A common indicator of water pollution is:
   a) CO₂ level
   b) Coliform bacteria ✔️
   c) Lead paint
   d) pH paper
   Explanation: Coliforms indicate fecal contamination in water.
8. Which one of the following diseases is directly related to poor sanitation?
   a) Diabetes
   b) Hypertension
   c) Cholera ✔️
   d) Cancer
   Explanation: Cholera is a waterborne disease caused by contaminated water.
9. Which part of the environment is mainly affected by poor solid waste management?
   a) Outer space
   b) Soil and groundwater ✔️
   c) Ozone layer
   d) Upper atmosphere
   Explanation: Decomposing waste pollutes soil and groundwater.
10. Which method is used for household wastewater treatment in rural areas?
    a) Septic tank ✔️
    b) Cooling tower
    c) Oil trap
    d) Chlorinator
    Explanation: Septic tanks treat domestic wastewater biologically.
11. Which of the following is a component of environmental sanitation?
    a) Solid waste disposal ✔️
    b) Road expansion
    c) Online education
    d) Traffic control
    Explanation: Solid waste management is essential for sanitation.
12. The full form of WHO is:
    a) World Health Organization ✔️
    b) World Hygiene Order
    c) Water Health Organization
    d) Wealth Health Office
    Explanation: WHO is responsible for international public health.
13. Leachate is produced from:
    a) Water purification
    b) Landfills ✔️
    c) Septic tanks only
    d) Oceans
    Explanation: Leachate is the liquid that drains from waste in landfills.
14. Open defecation is a major contributor to:
    a) Traffic jams
    b) Waterborne diseases ✔️
    c) Air pollution
    d) Noise pollution
    Explanation: It leads to contamination of water sources.
15. In environmental sanitation, the 3Rs stand for:
    a) Repeat, Reuse, Rotate
    b) Reduce, Reuse, Recycle ✔️
    c) Read, Recall, Respond
    d) Reboot, Restore, Repair
    Explanation: These are key principles of waste management.
16. A major cause of urban water pollution is:
    a) Natural springs
    b) Industrial effluents ✔️
    c) Green cover
    d) Organic farming
    Explanation: Industrial discharge contaminates water bodies.
17. The most common disinfectant used in water purification is:
    a) Alcohol
    b) Chlorine ✔️
    c) Mercury
    d) Ether
    Explanation: Chlorine kills pathogens in water.
18. Proper drainage systems help prevent:
    a) Waterlogging ✔️
    b) Overpopulation
    c) Deforestation
    d) Wind erosion
    Explanation: Good drainage avoids water stagnation.
19. Which agency in India is responsible for drinking water and sanitation?
    a) RBI
    b) Ministry of Jal Shakti ✔️
    c) NITI Aayog
    d) Ministry of Commerce
    Explanation: Jal Shakti oversees water-related services.
20. The best method to control mosquito breeding is:
    a) Air conditioning
    b) Eliminating stagnant water ✔️
    c) Increasing rainfall
    d) Planting flowers
    Explanation: Mosquitoes breed in stagnant water.

🟡 Moderate Level (21–40)

21. The Biochemical Oxygen Demand (BOD) is a measure of:
    a) Organic pollution in water ✔️
    b) Oxygen content in air
    c) Toxicity of solid waste
    d) Level of CO₂ in wastewater
    Explanation: BOD indicates the oxygen needed to break down organic matter.
22. Which of the following is a physical method of water purification?
    a) Sedimentation ✔️
    b) Chlorination
    c) UV disinfection
    d) Coagulation
    Explanation: Sedimentation involves physical settling of solids.
23. Grey water refers to:
    a) Contaminated industrial water
    b) Wastewater from kitchen and baths ✔️
    c) Sewage water
    d) Drinking water
    Explanation: Grey water excludes human waste and comes from domestic use.
24. Which type of latrine is suitable for water-scarce areas?
    a) Compost latrine ✔️
    b) Flush toilet
    c) Septic tank
    d) Community toilet
    Explanation: Compost toilets require little to no water.
25. Eutrophication in water bodies is caused by:
    a) Oil spills
    b) Excess nutrients ✔️
    c) Acid rain
    d) Industrial metals
    Explanation: Nutrient buildup causes algal blooms and oxygen depletion.
26. Which type of waste requires incineration?
    a) Biomedical waste ✔️
    b) Organic compost
    c) Glass bottles
    d) Paper waste
    Explanation: Biomedical waste is hazardous and must be incinerated.
27. The principal pathogen in fecal contamination is:
    a) Bacillus subtilis
    b) Escherichia coli ✔️
    c) Pseudomonas
    d) Clostridium
    Explanation: E. coli indicates fecal contamination.
28. The sludge from sewage treatment is usually:
    a) Dried and used as fertilizer ✔️
    b) Burned in open fields
    c) Discharged into rivers
    d) Dumped in the sea
    Explanation: Treated sludge can be reused agriculturally.
29. Nitrates in drinking water cause:
    a) Skin diseases
    b) Diarrhea
    c) Blue baby syndrome ✔️
    d) Cancer
    Explanation: High nitrates affect oxygen-carrying capacity in infants.
30. The first stage of sewage treatment is:
    a) Disinfection
    b) Screening ✔️
    c) Sedimentation
    d) Aeration
    Explanation: Screening removes large objects early on.
31. Which is the most suitable method for disinfecting a shallow well?
    a) Bleaching powder ✔️
    b) Boiling
    c) Chlorine gas
    d) UV treatment
    Explanation: Bleaching powder is practical and effective.
32. The World Toilet Day is observed on:
    a) October 10
    b) March 22
    c) November 19 ✔️
    d) January 25
    Explanation: It raises awareness on sanitation needs globally.
33. Fly breeding is best controlled by:
    a) Air sprays
    b) Fogging
    c) Proper waste disposal ✔️
    d) Acoustic repellents
    Explanation: Clean environments prevent fly infestation.
34. A sanitary landfill includes:
    a) Lined pit with soil cover ✔️
    b) Open burning
    c) River dumping
    d) Waste compaction only
    Explanation: Sanitary landfills are engineered to protect the environment.
35. A good indicator of recent fecal pollution in water is:
    a) Salmonella
    b) Giardia
    c) Fecal coliforms ✔️
    d) Vibrio
    Explanation: Fecal coliforms point to recent contamination.
36. A soak pit is used for:
    a) Solid waste storage
    b) Wastewater disposal ✔️
    c) Drinking water
    d) Ventilation
    Explanation: Soak pits allow wastewater to percolate into the ground.
37. The maximum safe limit of fluoride in drinking water (as per WHO) is:
    a) 0.5 mg/L
    b) 1.5 mg/L ✔️
    c) 2.0 mg/L
    d) 3.0 mg/L
    Explanation: Beyond 1.5 mg/L, fluoride may cause health issues.
38. Which of the following is a biological method of waste treatment?
    a) Anaerobic digestion ✔️
    b) Filtration
    c) UV radiation
    d) Chlorination
    Explanation: Anaerobic microbes break down organic matter.
39. Vent pipes in a latrine are meant to:
    a) Prevent bad odor ✔️
    b) Allow rainwater flow
    c) Release methane
    d) Prevent water loss
    Explanation: Ventilation pipes reduce odors and gases.
40. Which pathogen causes typhoid?
    a) Vibrio cholerae
    b) Salmonella typhi ✔️
    c) Shigella
    d) E. coli
    Explanation: Salmonella typhi is responsible for typhoid fever.

🔴 Hard Level (41–50)

41. The most efficient method for sludge stabilization is:
    a) Anaerobic digestion ✔️
    b) Filtration
    c) Flocculation
    d) Sand drying
    Explanation: Anaerobic digestion reduces pathogen load and volume.
42. Slow sand filters are most suitable for:
    a) Rural water supply ✔️
    b) Sea water treatment
    c) Industrial use
    d) Urban rainwater
    Explanation: They are low-tech, effective for small communities.
43. Which act in India governs water pollution?
    a) Environmental Act 1984
    b) Water (Prevention and Control of Pollution) Act 1974 ✔️
    c) Public Health Act
    d) Sanitation Act 2001
    Explanation: This law specifically targets water pollution control.
44. Methane in biogas comes from:
    a) Combustion
    b) Anaerobic digestion of organic matter ✔️
    c) Photosynthesis
    d) UV exposure
    Explanation: Methane is produced in anaerobic conditions.
45. Which component is least biodegradable?
    a) Kitchen waste
    b) Garden clippings
    c) Paper
    d) Plastic ✔️
    Explanation: Plastics take hundreds of years to decompose.
46. The pH range suitable for biological treatment of sewage is:
    a) 2–4
    b) 4–5
    c) 6.5–8.5 ✔️
    d) 9–10
    Explanation: Microorganisms thrive in this neutral range.
47. Bioindicators of water quality include:
    a) Algae and invertebrates ✔️
    b) Bacteria
    c) Organic waste
    d) Lead
    Explanation: Certain aquatic species indicate pollution levels.
48. The role of trickling filters in wastewater treatment is:
    a) Sediment removal
    b) Odor control
    c) Biological oxidation ✔️
    d) Flocculation
    Explanation: Microbes grow on media and degrade organics.
49. The main disadvantage of pit latrines is:
    a) High cost
    b) Requires electricity
    c) Groundwater contamination ✔️
    d) Complex design
    Explanation: Pit latrines can leach into groundwater.
50. Ultraviolet radiation in water treatment works by:
    a) Coagulation
    b) DNA damage to microbes ✔️
    c) Sedimentation
    d) Releasing chlorine
    Explanation: UV damages microbial DNA, making them inactive.