Environmental Engineering – Multiple Choice Questions (MCQs)

1. 37. What is the main source of fluoride in drinking water that causes fluorosis?

   • A. Industrial waste
   • B. Natural geological formations
   • C. Disinfectants
   • D. Agricultural fertilizers

2. 38. The process of removing salts from saline water to produce fresh water is called:

   • A. Filtration
   • B. Desalination
   • C. Chlorination
   • D. Sedimentation

3. 39. What is "Reverse Osmosis (RO)"?

   • A. A filtration process that removes dissolved solids from water using a semi-permeable membrane
   • B. A process of adding salts to water
   • C. A method of aerating water
   • D. A type of disinfection

4. 40. The presence of coliform bacteria in drinking water indicates:

   • A. Presence of beneficial bacteria
   • B. Contamination by fecal matter
   • C. Presence of dissolved minerals
   • D. Hardness of water

5. 41. What is "Hardness" of water?

   • A. Its resistance to flow
   • B. The concentration of dissolved mineral ions
   • C. especially calcium and magnesium
   • D. Its ability to clean

6. 42. What is the purpose of a "settling tank" in water treatment?

   • A. To mix chemicals
   • B. To allow heavier suspended particles to settle out
   • C. To filter water
   • D. To disinfect water

7. 43. Which type of filter uses sand and gravel layers to remove suspended solids and some microorganisms?

   • A. Activated carbon filter
   • B. Membrane filter
   • C. Rapid sand filter
   • D. Slow sand filter

8. 44. What is "Activated Carbon" used for in water treatment?

   • A. To add color to water
   • B. To remove dissolved organic compounds and odors
   • C. To kill bacteria
   • D. To increase hardness

9. 45. The "turbidity" of water refers to its:

   • A. Color
   • B. Temperature
   • C. Cloudiness or haziness
   • D. Smell

10. 46. What is the "permissible limit" for drinking water parameters?

    • A. The maximum allowed concentration of a substance in drinking water
    • B. The minimum allowed concentration of a substance in drinking water
    • C. The average concentration of a substance in drinking water
    • D. The ideal concentration of a substance in drinking water

11. 47. What is "Biological Filtration" in wastewater treatment?

    • A. Filtration using membranes
    • B. Using microorganisms to break down pollutants
    • C. Filtration using sand
    • D. Filtration using chemicals

12. 48. The purpose of "aeration" in wastewater treatment is to:

    • A. Remove solids
    • B. Increase dissolved oxygen for biological processes
    • C. Increase temperature
    • D. Decrease pH