Environmental Engineering MCQs for APSC PWD WRD JE 2025

30 Environmental Engineering MCQs for APSC JE PWD & Water Resources 2025

Topics Covered

• Water Quality
• Water Treatment
• Wastewater Treatment
• Air Pollution
• Solid Waste Management
• Environmental Legislation

Topic: Water Quality

1. What is the acceptable pH range for drinking water as per Indian standards?

a) 6.5 to 8.5 b) 5.0 to 7.0 c) 8.0 to 9.0 d) 4.5 to 6.5

Answer: a) 6.5 to 8.5
The pH range of 6.5 to 8.5 ensures water is neither too acidic nor too alkaline, making it safe for consumption.

Topic: Water Quality

2. Which parameter indicates the presence of organic matter in water?

a) Turbidity b) Biochemical Oxygen Demand (BOD) c) Hardness d) pH

Answer: b) Biochemical Oxygen Demand (BOD)
BOD measures the oxygen required by microorganisms to decompose organic matter in water.

Topic: Water Treatment

3. What is the primary purpose of aeration in water treatment?

a) Remove suspended solids b) Add oxygen and remove gases c) Kill pathogens d) Adjust pH

Answer: b) Add oxygen and remove gases
Aeration introduces oxygen and removes undesirable gases like carbon dioxide and hydrogen sulfide.

Topic: Water Treatment

4. Which chemical is commonly used as a coagulant in water treatment?

a) Sodium chloride b) Alum c) Calcium carbonate d) Potassium permanganate

Answer: b) Alum
Alum (aluminum sulfate) is widely used to destabilize particles, aiding in their removal during sedimentation.

Topic: Wastewater Treatment

5. What is the main function of a grit chamber in wastewater treatment?

a) Remove organic matter b) Settle heavy inorganic solids c) Disinfect wastewater d) Reduce BOD

Answer: b) Settle heavy inorganic solids
Grit chambers allow sand, gravel, and other heavy solids to settle, protecting downstream equipment.

Topic: Wastewater Treatment

6. In which stage of wastewater treatment is activated sludge process used?

a) Preliminary treatment b) Primary treatment c) Secondary treatment d) Tertiary treatment

Answer: c) Secondary treatment
The activated sludge process is a biological treatment used to remove organic matter in secondary treatment.

Topic: Air Pollution

7. Which gas is primarily responsible for the greenhouse effect?

a) Nitrogen b) Oxygen c) Carbon dioxide d) Sulfur dioxide

Answer: c) Carbon dioxide
Carbon dioxide traps heat in the atmosphere, contributing significantly to global warming.

Topic: Air Pollution

8. What device is used to remove particulate matter from industrial exhaust?

a) Scrubber b) Electrostatic precipitator c) Catalytic converter d) Cyclone separator

Answer: b) Electrostatic precipitator
It uses an electric charge to capture fine particles from exhaust gases.

Topic: Solid Waste Management

9. What is the process of converting organic waste into nutrient-rich soil called?

a) Incineration b) Composting c) Landfilling d) Pyrolysis

Answer: b) Composting
Composting transforms organic waste into humus, enriching soil fertility.

Topic: Solid Waste Management

10. Which method of solid waste disposal is least preferred environmentally?

a) Recycling b) Composting c) Open dumping d) Incineration

Answer: c) Open dumping
Open dumping pollutes soil, water, and air, posing significant environmental risks.

Topic: Environmental Legislation

11. Which Indian act regulates water pollution control?

a) Air Act, 1981 b) Water Act, 1974 c) Environment Protection Act, 1986 d) Forest Conservation Act, 1980

Answer: b) Water Act, 1974
It establishes standards and regulations to prevent and control water pollution.

Topic: Environmental Legislation

12. What is the primary goal of the Environment Protection Act, 1986?

a) Promote industrial growth b) Protect and improve environmental quality c) Regulate urban planning d) Encourage deforestation

Answer: b) Protect and improve environmental quality
The act aims to safeguard the environment through comprehensive regulations.

Topic: Water Quality

13. Hardness in water is primarily caused by which ions?

a) Sodium and potassium b) Calcium and magnesium c) Chloride and sulfate d) Nitrate and phosphate

Answer: b) Calcium and magnesium
These ions cause scaling and reduce soap efficiency in water.

Topic: Water Treatment

14. Which process removes dissolved salts from water?

a) Filtration b) Sedimentation c) Reverse osmosis d) Coagulation

Answer: c) Reverse osmosis
It uses a semi-permeable membrane to remove salts and impurities.

Topic: Wastewater Treatment

15. What is the detention time typically used in primary sedimentation tanks?

a) 2 to 4 hours b) 10 to 12 hours c) 30 to 60 minutes d) 24 hours

Answer: a) 2 to 4 hours
This allows sufficient time for solids to settle in primary treatment.

Topic: Air Pollution

16. Which pollutant is associated with acid rain?

a) Carbon monoxide b) Sulfur dioxide c) Ozone d) Particulate matter

Answer: b) Sulfur dioxide
It reacts with water vapor to form sulfuric acid, causing acid rain.

Topic: Solid Waste Management

17. What is the primary advantage of recycling?

a) Increases waste volume b) Reduces resource consumption c) Promotes landfilling d) Increases pollution

Answer: b) Reduces resource consumption
Recycling conserves raw materials and reduces the need for virgin resources.

Topic: Environmental Legislation

18. Which body enforces the Air Act, 1981 in India?

a) Central Pollution Control Board b) Ministry of Agriculture c) Forest Department d) Bureau of Indian Standards

Answer: a) Central Pollution Control Board
It monitors and regulates air pollution across the country.

Topic: Water Quality

19. Turbidity in water is measured in which unit?

a) ppm b) NTU c) mg/L d) pH

Answer: b) NTU
Nephelometric Turbidity Units measure the cloudiness of water.

Topic: Water Treatment

20. Chlorination in water treatment is primarily used to:

a) Remove hardness b) Disinfect water c) Adjust pH d) Remove color

Answer: b) Disinfect water
Chlorine kills pathogens, ensuring water is safe for consumption.

Topic: Wastewater Treatment

21. What is the purpose of a trickling filter?

a) Remove heavy metals b) Treat organic matter biologically c) Filter large debris d) Adjust wastewater pH

Answer: b) Treat organic matter biologically
It uses microorganisms to degrade organic pollutants in wastewater.

Topic: Air Pollution

22. What is the main source of carbon monoxide in urban areas?

a) Industrial emissions b) Vehicular exhaust c) Power plants d) Agricultural burning

Answer: b) Vehicular exhaust
Incomplete combustion in vehicles releases carbon monoxide.

Topic: Solid Waste Management

23. Which waste type is suitable for incineration?

a) Plastic bottles b) Organic waste c) Medical waste d) Glass

Answer: c) Medical waste
Incineration safely destroys hazardous medical waste at high temperatures.

Topic: Environmental Legislation

24. The National Ambient Air Quality Standards (NAAQS) in India are set by:

a) Ministry of Health b) Central Pollution Control Board c) Indian Meteorological Department d) Ministry of Urban Development

Answer: b) Central Pollution Control Board
It establishes air quality standards to protect public health.

Topic: Water Quality

25. What does high COD in wastewater indicate?

a) Low organic content b) High inorganic content c) High oxidizable pollutants d) Low bacterial activity

Answer: c) High oxidizable pollutants
Chemical Oxygen Demand measures pollutants that can be chemically oxidized.

Topic: Water Treatment

26. Slow sand filters are effective in removing:

a) Dissolved salts b) Bacteria c) Heavy metals d) Oil

Answer: b) Bacteria
Slow sand filters use biological processes to remove pathogens.

Topic: Wastewater Treatment

27. What is the byproduct of anaerobic sludge digestion?

a) Carbon dioxide only b) Methane and carbon dioxide c) Nitrogen gas d) Sulfur dioxide

Answer: b) Methane and carbon dioxide
Anaerobic digestion produces biogas, primarily methane and CO2.

Topic: Air Pollution

28. Photochemical smog is primarily caused by:

a) Sulfur dioxide b) Nitrogen oxides and VOCs c) Carbon dioxide d) Particulate matter

Answer: b) Nitrogen oxides and VOCs
These react in sunlight to form ozone and other pollutants.

Topic: Solid Waste Management

29. What is the first step in solid waste management?

a) Disposal b) Collection c) Treatment d) Recycling

Answer: b) Collection
Efficient collection ensures proper handling of waste for further processing.

Topic: Environmental Legislation

30. The Montreal Protocol aims to protect:

a) Biodiversity b) Ozone layer c) Water resources d) Forests

Answer: b) Ozone layer
It phases out substances that deplete the ozone layer, like CFCs.