Environmental Engineering MCQs for APSC JE 2025

Additional 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

31. What is the maximum permissible limit of fluoride in drinking water as per IS 10500?

a) 0.5 mg/L b) 1.0 mg/L c) 1.5 mg/L d) 2.0 mg/L

Answer: c) 1.5 mg/L
Excess fluoride can cause fluorosis; IS 10500 sets the limit at 1.5 mg/L.

Topic: Water Quality

32. Which ion causes alkalinity in water?

a) Chloride b) Bicarbonate c) Nitrate d) Sulfate

Answer: b) Bicarbonate
Bicarbonate ions contribute to water’s ability to neutralize acids.

Topic: Water Quality

33. What does high coliform count in water indicate?

a) Heavy metal contamination b) Fecal pollution c) Excessive salinity d) Low oxygen levels

Answer: b) Fecal pollution
Coliform bacteria suggest contamination from human or animal waste.

Topic: Water Quality

34. What is the desirable limit for total dissolved solids (TDS) in drinking water?

a) 200 mg/L b) 500 mg/L c) 1000 mg/L d) 1500 mg/L

Answer: b) 500 mg/L
IS 10500 recommends TDS below 500 mg/L for palatable water.

Topic: Water Quality

35. Which parameter is used to measure water clarity?

a) BOD b) Turbidity c) Hardness d) Alkalinity

Answer: b) Turbidity
Turbidity measures the cloudiness caused by suspended particles.

Topic: Water Quality

36. What is eutrophication in water bodies?

a) Oxygen depletion b) Nutrient enrichment causing algal blooms c) Heavy metal contamination d) Temperature increase

Answer: b) Nutrient enrichment causing algal blooms
Excess nitrogen and phosphorus lead to algal growth, harming aquatic life.

Topic: Water Treatment

37. What is the purpose of flocculation in water treatment?

a) Kill pathogens b) Form larger particles from coagulated solids c) Remove dissolved salts d) Adjust water pH

Answer: b) Form larger particles from coagulated solids
Flocculation aggregates particles for easier removal in sedimentation.

Topic: Water Treatment

38. Which process softens water by removing calcium and magnesium ions?

a) Filtration b) Ion exchange c) Aeration d) Sedimentation

Answer: b) Ion exchange
It replaces hardness-causing ions with sodium ions.

Topic: Water Treatment

39. What is the main purpose of rapid sand filtration?

a) Remove bacteria b) Remove suspended solids c) Reduce hardness d) Eliminate odors

Answer: b) Remove suspended solids
It filters fine particles after coagulation and sedimentation.

Topic: Water Treatment

40. What chemical is used to remove iron from water?

a) Chlorine b) Potassium permanganate c) Alum d) Lime

Answer: b) Potassium permanganate
It oxidizes iron, allowing it to precipitate and be filtered out.

Topic: Water Treatment

41. What is the contact time for effective chlorination?

a) 5 minutes b) 20 minutes c) 1 hour d) 2 hours

Answer: b) 20 minutes
This ensures sufficient time for chlorine to disinfect water.

Topic: Water Treatment

42. What is the purpose of activated carbon in water treatment?

a) Remove hardness b) Adsorb organic compounds c) Kill bacteria d) Adjust pH

Answer: b) Adsorb organic compounds
It removes odors, tastes, and organic pollutants.

Topic: Wastewater Treatment

43. What is the purpose of a bar screen in wastewater treatment?

a) Remove fine particles b) Capture large debris c) Reduce BOD d) Disinfect water

Answer: b) Capture large debris
Bar screens remove sticks, plastics, and other large objects in preliminary treatment.

Topic: Wastewater Treatment

44. What is the main goal of tertiary wastewater treatment?

a) Remove large solids b) Reduce organic matter c) Remove nutrients and pathogens d) Settle grit

Answer: c) Remove nutrients and pathogens
It ensures water is safe for reuse or discharge.

Topic: Wastewater Treatment

45. What is the function of an oxidation ditch?

a) Remove heavy metals b) Treat wastewater biologically c) Filter solids d) Store sludge

Answer: b) Treat wastewater biologically
It uses aeration to promote microbial degradation of organic matter.

Topic: Wastewater Treatment

46. What does high BOD in effluent indicate?

a) Low organic pollution b) High oxygen availability c) High organic pollution d) Low pathogen content

Answer: c) High organic pollution
High BOD shows significant organic matter requiring oxygen for decomposition.

Topic: Wastewater Treatment

47. What is the purpose of sludge thickening?

a) Increase water content b) Reduce sludge volume c) Remove pathogens d) Add nutrients

Answer: b) Reduce sludge volume
It concentrates solids for easier handling and disposal.

Topic: Wastewater Treatment

48. Which gas is produced during aerobic wastewater treatment?

a) Methane b) Carbon dioxide c) Hydrogen sulfide d) Ammonia

Answer: b) Carbon dioxide
Aerobic processes oxidize organic matter, releasing CO2.

Topic: Air Pollution

49. What is the primary function of a bag filter?

a) Remove gaseous pollutants b) Capture particulate matter c) Reduce ozone levels d) Neutralize acid gases

Answer: b) Capture particulate matter
Bag filters trap dust and particles from industrial emissions.

Topic: Air Pollution

50. Which pollutant is monitored under PM2.5 standards?

a) Carbon monoxide b) Fine particulate matter c) Sulfur dioxide d) Nitrogen dioxide

Answer: b) Fine particulate matter
PM2.5 includes particles smaller than 2.5 microns, harmful to health.

Topic: Air Pollution

51. What is the primary source of ozone at ground level?

a) Natural emissions b) Photochemical reactions c) Volcanic activity d) Forest fires

Answer: b) Photochemical reactions
Ozone forms from NOx and VOCs reacting in sunlight.

Topic: Air Pollution

52. What device reduces vehicle exhaust emissions?

a) Scrubber b) Cyclone separator c) Catalytic converter d) Bag filter

Answer: c) Catalytic converter
It converts harmful gases like CO and NOx into less toxic substances.

Topic: Air Pollution

53. What is the Air Quality Index (AQI) used for?

a) Measure rainfall b) Assess air pollution levels c) Monitor water quality d) Calculate noise levels

Answer: b) Assess air pollution levels
AQI indicates air quality and its impact on health.

Topic: Air Pollution

54. Which gas causes respiratory issues in high concentrations?

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

Answer: c) Sulfur dioxide
It irritates the respiratory system and can cause asthma attacks.

Topic: Solid Waste Management

55. What is the purpose of a sanitary landfill?

a) Burn waste b) Safely dispose of waste with liners c) Compost inorganic waste d) Recycle all waste

Answer: b) Safely dispose of waste with liners
It uses liners and covers to prevent environmental contamination.

Topic: Solid Waste Management

56. What is the hierarchy of waste management?

a) Disposal, treatment, recycling b) Reduce, reuse, recycle c) Incineration, landfilling, composting d) Collection, disposal, storage

Answer: b) Reduce, reuse, recycle
This prioritizes minimizing waste generation and resource use.

Topic: Solid Waste Management

57. What is leachate in a landfill?

a) Gas produced from waste b) Liquid from decomposing waste c) Recycled material d) Burned ash

Answer: b) Liquid from decomposing waste
Leachate can pollute groundwater if not properly managed.

Topic: Solid Waste Management

58. What is the main benefit of waste segregation?

a) Increases disposal costs b) Enhances recycling efficiency c) Promotes landfilling d) Reduces waste collection

Answer: b) Enhances recycling efficiency
Segregation separates recyclables, reducing waste to landfills.

Topic: Solid Waste Management

59. Which waste is classified as hazardous?

a) Food scraps b) Batteries c) Paper d) Glass bottles

Answer: b) Batteries
They contain toxic chemicals requiring special disposal.

Topic: Solid Waste Management

60. What is vermicomposting?

a) Burning waste b) Composting with worms c) Recycling plastics d) Landfilling waste

Answer: b) Composting with worms
Earthworms break down organic waste into nutrient-rich compost.