1. Which of the following is NOT a major source of wastewater?

a) Domestic wastewater
b) Industrial wastewater
c) Agricultural runoff
d) Groundwater

Answer: d) Groundwater

2. Which type of wastewater mainly originates from households and residential areas?

a) Domestic wastewater
b) Industrial wastewater
c) Stormwater runoff
d) Agricultural wastewater

Answer: a) Domestic wastewater

3. Wastewater from industries often contains high levels of:

a) Organic matter only

b) Heavy metals and chemicals
c) Only biodegradable substances
d) None of the above

Answer: b) Heavy metals and chemicals

4. Which of the following is a major source of wastewater pollution in urban areas?

a) Sewage from households

b) Industrial discharge
c) Stormwater runoff
d) All of the above

Answer: d) All of the above

5. What is the main concern with agricultural wastewater?

a) Presence of pathogens
b) High concentration of nitrogen and phosphorus
c) Excessive temperature changes
d) High levels of dissolved oxygen

Answer: b) High concentration of nitrogen and phosphorus

6. Which source contributes to wastewater through runoff from roads and urban surfaces?

a) Industrial wastewater
b) Domestic wastewater
c) Stormwater runoff
d) Groundwater recharge

Answer: c) Stormwater runoff

7. Groundwater contamination from wastewater sources is mainly caused by:

a) Leaking septic tanks

b) Industrial effluents
c) Agricultural chemical runoff
d) All of the above

Answer: d) All of the above

8. Which of the following is the best way to reduce industrial wastewater pollution?

a) Discharging untreated wastewater into rivers

b) Implementing wastewater treatment plants
c) Increasing industrial production
d) Ignoring pollution regulations

Answer: b) Implementing wastewater treatment plants

9. Which type of wastewater treatment is primarily used for removing solids and organic
matter?

a) Primary treatment
b) Secondary treatment
c) Tertiary treatment
d) None of the above

Answer: a) Primary treatment

10. What is the primary goal of wastewater treatment?

a) To increase water pollution

b) To remove contaminants before releasing water back to the environment
c) To generate more wastewater
d) To increase chemical content in water

Answer: b) To remove contaminants before releasing water back to the environment

11. Why is maintaining the water cycle important?

a) To ensure continuous availability of freshwater
b) To increase water pollution
c) To eliminate the need for rainfall
d) To stop groundwater recharge

Answer: a) To ensure continuous availability of freshwater

12. Which human activity disrupts the natural water cycle the most?

a) Reforestation
b) Overuse of groundwater and deforestation
c) Rainwater harvesting
d) Recycling wastewater

Answer: b) Overuse of groundwater and deforestation

13. What is one of the best ways to maintain the water cycle?

a) Increase deforestation
b) Reduce pollution and conserve water
c) Dump waste into rivers
d) Extract groundwater without limits

Answer: b) Reduce pollution and conserve water

14. How does afforestation help in maintaining the water cycle?

a) By increasing surface runoff

b) By enhancing groundwater recharge and rainfall
c) By reducing cloud formation
d) By preventing water absorption
Answer: b) By enhancing groundwater recharge and rainfall

15. Which of the following is a sustainable method to maintain the water cycle?

a) Constructing rainwater harvesting systems

b) Polluting rivers with industrial waste
c) Over-pumping groundwater
d) Cutting down forests near water bodies

Answer: a) Constructing rainwater harvesting systems

16. What role do wetlands play in maintaining the water cycle?

a) They store and purify water

b) They increase desertification
c) They block groundwater recharge
d) They cause water scarcity

Answer: a) They store and purify water

17. How does wastewater treatment contribute to maintaining the water cycle?

a) By allowing safe reuse and discharge of treated water

b) By increasing water pollution
c) By reducing freshwater availability
d) By eliminating the need for water conservation

Answer: a) By allowing safe reuse and discharge of treated water

18. What is the effect of climate change on the water cycle?

a) It disrupts rainfall patterns and increases droughts and floods
b) It improves water conservation
c) It stabilizes groundwater levels
d) It has no impact on the water cycle

Answer: a) It disrupts rainfall patterns and increases droughts and floods

19. Why should industries adopt water recycling methods?

a) To reduce freshwater consumption and maintain water balance

b) To increase wastewater discharge into rivers
c) To extract more groundwater without regulation
d) To make water resources scarce

Answer: a) To reduce freshwater consumption and maintain water balance

20. What is the main function of watersheds in the water cycle?

a) To collect and store water for ecosystems and human use

b) To drain all water into the ocean
c) To prevent groundwater recharge
d) To remove moisture from the environment

Answer: a) To collect and store water for ecosystems and human use

21. Which of the following is considered an impurity in water?

a) Oxygen
b) Dissolved salts
c) Hydrogen
d) Pure H₂O molecules

Answer: b) Dissolved salts

22. Which type of impurity causes hardness in water?

a) Dissolved oxygen
b) Calcium and magnesium salts
c) Hydrogen ions
d) Sodium chloride

Answer: b) Calcium and magnesium salts

23. What is the main health effect of drinking water contaminated with heavy metals like
lead and mercury?

a) Improved digestion
b) Neurological and kidney damage
c) Increased oxygen levels
d) Faster metabolism

Answer: b) Neurological and kidney damage

24. What kind of impurities in water can cause diseases like cholera and typhoid?

a) Biological impurities (bacteria, viruses)

b) Suspended particles
c) Hardness-causing minerals
d) Dissolved gases

Answer: a) Biological impurities (bacteria, viruses)

25. High levels of nitrates in drinking water can cause:

a) Blue baby syndrome (methemoglobinemia)
b) Increased muscle growth
c) Better taste in water
d) Stronger bones

Answer: a) Blue baby syndrome (methemoglobinemia)

26. How do suspended impurities like sand and silt affect water?

a) Make it clearer and healthier

b) Increase turbidity and clog pipelines
c) Improve taste
d) Make it lighter in density

Answer: b) Increase turbidity and clog pipelines

27. Which impurity in water is responsible for an unpleasant smell and taste?

a) Dissolved oxygen
b) Hydrogen sulfide (H₂S)
c) Calcium carbonate
d) Magnesium sulfate

Answer: b) Hydrogen sulfide (H₂S)

28. How do chemical impurities like pesticides and industrial waste affect water bodies?

a) They increase biodiversity

b) They cause water pollution and harm aquatic life
c) They make water more drinkable
d) They improve soil fertility
Answer: b) They cause water pollution and harm aquatic life

29. What is the primary effect of high levels of dissolved salts in water?

a) Enhances the taste of water

b) Causes scaling in pipes and appliances
c) Increases the oxygen content in water
d) Reduces water density

Answer: b) Causes scaling in pipes and appliances

30. Which method is most effective in removing biological impurities from drinking water?

a) Boiling and chlorination

b) Adding more minerals
c) Increasing water temperature
d) Shaking the water vigorously

Answer: a) Boiling and chlorination

31. Which of the following is a physical parameter of water quality?

a) pH
b) Turbidity
c) Dissolved oxygen
d) Nitrate concentration

Answer: b) Turbidity

32. What does the pH level of water indicate?

a) The temperature of the water

b) The acidity or alkalinity of water
c) The hardness of water
d) The biological contamination in water
Answer: b) The acidity or alkalinity of water

33. Which physical parameter affects the clarity of water?

a) Hardness
b) Turbidity
c) Dissolved oxygen
d) pH level

Answer: b) Turbidity

34. What is the ideal pH range for drinking water as per WHO standards?

a) 2-4
b) 5-6
c) 6.5-8.5
d) 9-11

Answer: c) 6.5-8.5

35. Which of the following is a biological water quality parameter?

a) Total dissolved solids (TDS)

b) Biochemical Oxygen Demand (BOD)
c) Heavy metal concentration
d) Nitrate levels

Answer: b) Biochemical Oxygen Demand (BOD)

36. High levels of which chemical parameter in water can lead to eutrophication?

a) Chlorine
b) Phosphates and nitrates
c) Lead and mercury
d) Dissolved oxygen

Answer: b) Phosphates and nitrates

37. Which biological parameter is commonly used to indicate the presence of
sewage contamination in water?

a) Turbidity
b) Escherichia coli (E. coli)
c) Total dissolved solids (TDS)
d) Hardness

Answer: b) Escherichia coli (E. coli)

38. What does the term "Total Dissolved Solids (TDS)" refer to?

a) The number of bacteria in water

b) The amount of organic matter in water
c) The total concentration of dissolved substances in water
d) The hardness level of water

Answer: c) The total concentration of dissolved substances in water

39. Which of the following chemical parameters is essential for aquatic life?

a) Dissolved oxygen (DO)

b) Nitrate
c) Ammonia
d) Lead

Answer: a) Dissolved oxygen (DO)

40. A high Biochemical Oxygen Demand (BOD) value in water indicates:

a) High water purity

b) High level of organic pollution
c) Low microbial activity
d) Absence of contaminants

Answer: b) High level of organic pollution

41. What is the ideal pH range of potable water?

a) 2-4
b) 4.5-5.5
c) 6.5-8.5
d) 9-11

Answer: c) 6.5-8.5

42. Which of the following is NOT a characteristic of potable water?

a) Free from harmful bacteria

b) High levels of heavy metals
c) Odorless and tasteless
d) Free from suspended particles

Answer: b) High levels of heavy metals

43. What should be the turbidity level of potable water?

a) Less than 1 NTU

b) 10-15 NTU
c) 50 NTU
d) More than 100 NTU

Answer: a) Less than 1 NTU

44. Which biological characteristic must potable water have?

a) Presence of E. coli
b) Free from harmful bacteria and viruses
c) Presence of organic pollutants
d) Presence of algae

Answer: b) Free from harmful bacteria and viruses

45. Which of the following chemicals is used to disinfect potable water?

a) Mercury
b) Chlorine
c) Lead
d) Arsenic

Answer: b) Chlorine

46. Total Dissolved Solids (TDS) in potable water should be below:

a) 500 mg/L
b) 1000 mg/L
c) 2000 mg/L
d) 5000 mg/L

Answer: a) 500 mg/L

47. What is the minimum dissolved oxygen (DO) level required in potable water?

a) 0 mg/L
b) 2 mg/L
c) 5 mg/L
d) 10 mg/L

Answer: c) 5 mg/L

48. Which metal should NOT be present in potable water?

a) Iron
b) Copper
c) Lead
d) Magnesium

Answer: c) Lead

49. Hardness in potable water should be within which range?

a) Below 10 mg/L
b) 75-150 mg/L
c) 500-1000 mg/L
d) Above 2000 mg/L

Answer: b) 75-150 mg/L

50. Why should potable water be free from coliform bacteria?

a) It improves taste
b) It prevents diseases like typhoid and cholera
c) It increases oxygen levels
d) It makes water appear clear

Answer: b) It prevents diseases like typhoid and cholera

51. What is the maximum permissible pH range for wastewater effluent discharge as per
most environmental regulations?

a) 2-4
b) 4.5-5.5
c) 6.5-8.5
d) 10-12

Answer: c) 6.5-8.5

52. What is the standard limit for Biochemical Oxygen Demand (BOD) in treated
wastewater for safe discharge into surface water bodies?

a) Less than 10 mg/L

b) 30 mg/L
c) 100 mg/L
d) 500 mg/L

Answer: b) 30 mg/L
53. What is the maximum allowable Total Suspended Solids (TSS) in treated wastewater
effluent?

a) 10 mg/L
b) 50 mg/L
c) 250 mg/L
d) 1000 mg/L

Answer: b) 50 mg/L

54. What should be the minimum Dissolved Oxygen (DO) level in treated wastewater
before discharge into water bodies?

a) 0 mg/L
b) 2 mg/L
c) 4-5 mg/L
d) 10 mg/L

Answer: c) 4-5 mg/L

55. What is the acceptable limit of Chemical Oxygen Demand (COD) in treated wastewater
discharge?

a) 10 mg/L
b) 50 mg/L
c) 250 mg/L
d) 1000 mg/L

Answer: c) 250 mg/L

56. Which of the following toxic metals has a strict permissible limit in wastewater effluent
standards?

a) Iron
b) Lead
c) Calcium
d) Magnesium

Answer: b) Lead

57. What is the maximum allowable concentration of nitrates (NO₃) in treated wastewater
effluent?

a) 1 mg/L
b) 10 mg/L
c) 50 mg/L
d) 500 mg/L

Answer: c) 50 mg/L

58. Why is it important to regulate phosphorus levels in wastewater effluent?

a) It reduces water turbidity

b) It prevents eutrophication in water bodies
c) It increases microbial activity
d) It improves the taste of water

Answer: b) It prevents eutrophication in water bodies

59. What is the permissible limit of fecal coliform bacteria in treated wastewater for safe
discharge?
a) 0 MPN/100 mL
b) 10 MPN/100 mL
c) 1000 MPN/100 mL
d) 10,000 MPN/100 mL

Answer: a) 0 MPN/100 mL

60. What is the importance of regulating Total Dissolved Solids (TDS) in wastewater
effluent?

a) To prevent clogging of pipelines

b) To maintain the aesthetic quality of water
c) To protect aquatic life and prevent water salinity issues
d) To make water taste better

Answer: c) To protect aquatic life and prevent water salinity issues

61. What does the Water Quality Index (WQI) measure?

a) The aesthetic appeal of water

b) The overall quality of water based on multiple parameters
c) The hardness of water only
d) The quantity of water available

Answer: b) The overall quality of water based on multiple parameters

62. Which of the following parameters is NOT typically included in the calculation of
WQI?

a) pH
b) Dissolved Oxygen (DO)
c) Biochemical Oxygen Demand (BOD)
d) Water temperature only
Answer: d) Water temperature only

63. A high WQI value (above 100) generally indicates that the water is:

a) Excellent for drinking

b) Moderately polluted
c) Highly polluted and unsafe
d) Suitable for industrial use

Answer: c) Highly polluted and unsafe

64. Which organization provides international guidelines for water quality indices?

a) WHO (World Health Organization)

b) FIFA
c) UNESCO
d) NASA

Answer: a) WHO (World Health Organization)

65. What does a WQI score between 0-25 typically indicate?

a) Excellent water quality

b) Poor water quality
c) Highly polluted water
d) Water that requires immediate treatment

Answer: a) Excellent water quality

66. Which of the following parameters is used to assess the organic pollution in water
quality indices?

a) Total Dissolved Solids (TDS)

b) Biochemical Oxygen Demand (BOD)
c) Electrical Conductivity
d) Temperature

Answer: b) Biochemical Oxygen Demand (BOD)

67. What is the role of Dissolved Oxygen (DO) in determining water quality?

a) Higher DO indicates good water quality and supports aquatic life

b) Lower DO is preferred for better water quality
c) DO is not considered in WQI calculations
d) Higher DO makes water more acidic

Answer: a) Higher DO indicates good water quality and supports aquatic life

68. Which type of water body is likely to have the lowest WQI?

a) A clean mountain spring

b) A heavily polluted industrial wastewater stream
c) A freshwater lake with high biodiversity
d) A protected groundwater source

Answer: b) A heavily polluted industrial wastewater stream

69. What is the main advantage of using a Water Quality Index (WQI)?

a) It simplifies complex water quality data into a single number

b) It eliminates the need for laboratory testing
c) It increases water pollution levels
d) It ignores chemical contaminants

Answer: a) It simplifies complex water quality data into a single number

70. In WQI calculation, Total Coliform Bacteria is used to assess:

a) Water hardness
b) Biological contamination
c) Electrical conductivity
d) Temperature variation

Answer: b) Biological contamination

71. Why is water treatment essential before it is made available for public consumption?

a) To improve its taste

b) To remove harmful contaminants and pathogens
c) To increase its temperature
d) To add more nutrients

Answer: b) To remove harmful contaminants and pathogens

72. Which of the following is a key reason for treating wastewater?

a) To remove color from water

b) To reduce environmental pollution and protect aquatic life
c) To increase the concentration of minerals
d) To make the water more acidic

Answer: b) To reduce environmental pollution and protect aquatic life

73. What is the main concern if wastewater is discharged untreated into water bodies?

a) It can reduce the oxygen levels and harm aquatic ecosystems

b) It can increase the water's pH to unsafe levels
c) It can increase the temperature of water bodies
d) It improves the quality of surface water

Answer: a) It can reduce the oxygen levels and harm aquatic ecosystems

74. What is the main objective of drinking water treatment?

a) To increase the water's pH

b) To remove contaminants that could cause diseases
c) To increase the temperature for better taste
d) To increase the water's hardness

Answer: b) To remove contaminants that could cause diseases

75. Which of the following waterborne diseases can be prevented through proper water
treatment?

a) Malaria
b) Cholera
c) Tuberculosis
d) Influenza

Answer: b) Cholera

76. Why is wastewater treatment important for public health?

a) It helps to convert wastewater into usable drinking water

b) It removes harmful microorganisms and chemicals that can cause diseases
c) It increases the amount of water available for consumption
d) It adds nutrients to the water to promote better health

Answer: b) It removes harmful microorganisms and chemicals that can cause diseases

77. Which of the following is a potential consequence of untreated wastewater entering

rivers or lakes?

a) Increased water clarity

b) Eutrophication and algal blooms
c) Improved aquatic life diversity
d) Decreased turbidity

Answer: b) Eutrophication and algal blooms

78. What is the main benefit of using water treatment processes like filtration and
chlorination?

a) To increase the amount of water in the reservoir

b) To remove unwanted minerals and salts
c) To make the water safe for drinking and other uses
d) To change the water’s pH to neutral

Answer: c) To make the water safe for drinking and other uses

79. Why should wastewater treatment include the removal of organic matter?

a) To improve the smell of the water

b) To prevent the depletion of oxygen in the water
c) To increase the nutrients for aquatic life
d) To reduce the water temperature
Answer: b) To prevent the depletion of oxygen in the water

80. How does wastewater treatment help in protecting the environment?

a) It allows the wastewater to be reused for irrigation

b) It ensures that harmful chemicals and pathogens are removed before discharge
c) It increases the salinity of water bodies
d) It helps to increase the water’s hardness for industrial use

Answer: b) It ensures that harmful chemicals and pathogens are removed before discharge

81. The Water (Prevention and Control of Pollution) Act was enacted in which year?

a) 1974
b) 1981
c) 1972
d) 1990

Answer: c) 1972

82. The Clean Water State Revolving Fund (CWSRF) in the United States provides
financial assistance for which of the following?

a) Drinking water treatment plants

b) Wastewater treatment infrastructure
c) Air pollution control
d) Industrial waste management

Answer: b) Wastewater treatment infrastructure

83. Under the Water (Prevention and Control of Pollution) Act, who is responsible for
enforcing the water quality standards in India?
a) Ministry of Health
b) Central Pollution Control Board (CPCB)
c) Ministry of Environment
d) National Green Tribunal (NGT)

Answer: b) Central Pollution Control Board (CPCB)

84. Which international agreement focuses on the protection and sustainable use of water
resources?

a) The Kyoto Protocol

b) The Paris Agreement
c) The Ramsar Convention
d) The Water Framework Directive (EU)

Answer: d) The Water Framework Directive (EU)

85. The Clean Water Act (CWA) in the United States primarily addresses:

a) Soil erosion
b) Water pollution and quality standards
c) Air pollution
d) Hazardous waste disposal

Answer: b) Water pollution and quality standards

86. The Environmental Protection Agency (EPA) in the U.S. is responsible for:

a) Enforcing environmental regulations

b) Setting water quality standards for drinking water
c) Monitoring air and water quality
d) All of the above

Answer: d) All of the above

87. Which environmental law in India deals with the treatment and disposal of industrial
effluents?

a) The Air (Prevention and Control of Pollution) Act

b) The Environment Protection Act
c) The Water (Prevention and Control of Pollution) Act
d) The National Green Tribunal Act

Answer: c) The Water (Prevention and Control of Pollution) Act

88. Which of the following is NOT a function of the National Green Tribunal (NGT) in
India?

a) Enforcing water quality standards

b) Handling environmental disputes and cases
c) Promoting renewable energy
d) Reviewing environmental matters under various environmental laws

Answer: c) Promoting renewable energy

89. The Pollution Control Board in India is responsible for:

a) Issuing licenses for water treatment plants

b) Conducting research on water quality
c) Ensuring compliance with environmental laws for air, water, and land pollution
d) Setting water tariffs
Answer: c) Ensuring compliance with environmental laws for air, water, and land pollution

90. The United Nations Sustainable Development Goal (SDG) 6 focuses on:

a) Reducing industrial pollution

b) Ensuring availability and sustainable management of water and sanitation
c) Protecting marine ecosystems
d) Reducing carbon emissions from water treatment

Answer: b) Ensuring availability and sustainable management of water and sanitation

91. What is the maximum permissible limit of fluoride in drinking water

according to WHO?

a) 0.5 mg/L
b) 1.5 mg/L
c) 3.0 mg/L
d) 5.0 mg/L

Answer: b) 1.5 mg/L

92. The permissible limit of Total Suspended Solids (TSS) in treated wastewater
effluent is:

a) 5 mg/L
b) 10 mg/L
c) 30 mg/L
d) 50 mg/L

Answer: d) 50 mg/L

93. According to the WHO, the acceptable limit of Chlorine Residual in drinking
water is:

a) 0.1-0.2 mg/L
b) 0.5-1.0 mg/L
c) 1.5-2.0 mg/L
d) 2.5-3.0 mg/L

Answer: b) 0.5-1.0 mg/L

94. What is the maximum permissible level of Biochemical Oxygen Demand

(BOD) in treated wastewater effluent?

a) 1 mg/L
b) 5 mg/L
c) 10 mg/L
d) 30 mg/L

Answer: d) 30 mg/L

95. The permissible limit of pH in drinking water is:

a) 4.0-6.5
b) 6.5-8.5
c) 8.5-10
d) 10-12

Answer: b) 6.5-8.5

96. The primary objective of wastewater treatment is to:

a) Increase its pH
b) Remove harmful chemicals and pathogens
c) Add nutrients for aquatic life
d) Improve its color

Answer: b) Remove harmful chemicals and pathogens

97. What is the permissible level of Total Dissolved Solids (TDS) in drinking
water according to WHO?
a) 300 mg/L
b) 500 mg/L
c) 1000 mg/L
d) 1500 mg/L

Answer: b) 500 mg/L

98. The permissible limit for nitrate concentration in drinking water is:

a) 10 mg/L
b) 20 mg/L
c) 50 mg/L
d) 100 mg/L

Answer: a) 10 mg/L

99. Which of the following is a guideline value for fecal coliform in drinking
water according to WHO?

a) 0 MPN/100 mL
b) 50 MPN/100 mL
c) 100 MPN/100 mL
d) 500 MPN/100 mL

Answer: a) 0 MPN/100 mL

100. What is the permissible limit of lead concentration in drinking water

according to the US EPA?

a) 0.01 mg/L
b) 0.05 mg/L
c) 0.1 mg/L
d) 0.15 mg/L

Answer: a) 0.01 mg/L

101. The permissible limit for pH in wastewater effluent is:

a) 4.0-5.0
b) 5.5-9.0
c) 6.0-8.0
d) 7.0-10.0

Answer: b) 5.5-9.0

102. Which of the following is a standard for wastewater treatment plants to

remove nitrogen?

a) Chemical precipitation
b) Biological denitrification
c) Membrane filtration
d) Reverse osmosis

Answer: b) Biological denitrification

103. What is the maximum allowable concentration of arsenic in drinking water

as per WHO?

a) 0.01 mg/L
b) 0.05 mg/L
c) 0.1 mg/L
d) 0.2 mg/L

Answer: a) 0.01 mg/L

104. The acceptable limit for dissolved oxygen (DO) in wastewater effluent is:

a) 0.5 mg/L
b) 1.0 mg/L
c) 3.0 mg/L
d) 5.0 mg/L

Answer: d) 5.0 mg/L

105. What is the permissible limit of copper in drinking water?

a) 0.01 mg/L
b) 0.2 mg/L
c) 0.5 mg/L
d) 1.0 mg/L

Answer: b) 0.2 mg/L

106. The permissible limit of ammonia nitrogen in treated wastewater is

generally:

a) 0.5 mg/L
b) 5.0 mg/L
c) 10.0 mg/L
d) 50.0 mg/L

Answer: a) 0.5 mg/L

107. Which of the following is the primary standard for wastewater discharge
into surface water bodies?

a) BOD
b) Hardness
c) Chlorine Residual
d) Fluoride

Answer: a) BOD

108. What is the maximum permissible concentration of mercury in wastewater

effluent?

a) 0.001 mg/L
b) 0.005 mg/L
c) 0.01 mg/L
d) 0.1 mg/L

Answer: a) 0.001 mg/L

109. Which of the following is considered a toxic substance that must be removed
from wastewater before discharge?

a) Phosphorus
b) Lead
c) Nitrogen
d) Oxygen

Answer: b) Lead

110. Which law regulates the discharge of effluent into water bodies in India?

a) The Environment Protection Act, 1986

b) The Water (Prevention and Control of Pollution) Act, 1974
c) The Air (Prevention and Control of Pollution) Act, 1981
d) The National Green Tribunal Act, 2010

Answer: b) The Water (Prevention and Control of Pollution) Act, 1974

111. What is the permissible limit of sulfur in drinking water?

a) 0.1 mg/L
b) 0.2 mg/L
c) 0.5 mg/L
d) 1.0 mg/L

Answer: a) 0.1 mg/L

112. The effluent standard for zinc in wastewater is generally set at:

a) 0.1 mg/L
b) 1.0 mg/L
c) 5.0 mg/L
d) 10.0 mg/L

Answer: b) 1.0 mg/L

113. The permissible level of manganese in drinking water is:

a) 0.05 mg/L
b) 0.1 mg/L
c) 0.3 mg/L
d) 0.5 mg/L

Answer: b) 0.1 mg/L

114. According to the US EPA, the total coliform bacteria level in drinking water
must be:

a) 0 MPN/100 mL
b) 10 MPN/100 mL
c) 50 MPN/100 mL
d) 100 MPN/100 mL

Answer: a) 0 MPN/100 mL

115. The permissible concentration of oil and grease in wastewater effluent is:

a) 5 mg/L
b) 10 mg/L
c) 50 mg/L
d) 100 mg/L

Answer: b) 10 mg/L

116. The allowable concentration of chlorine in treated wastewater before

discharge should be:

a) 0.2 mg/L
b) 1.0 mg/L
c) 2.0 mg/L
d) 5.0 mg/L

Answer: a) 0.2 mg/L

117. According to the WHO, the recommended limit of turbidity in drinking
water is:

a) 1 NTU
b) 5 NTU
c) 10 NTU
d) 15 NTU

Answer: a) 1 NTU

118. Which of the following is NOT a standard parameter for wastewater

discharge?

a) Total Phosphorus
b) Total Nitrogen
c) Total Alkalinity
d) Total BOD

Answer: c) Total Alkalinity

119. What is the standard limit for the presence of coliform bacteria in drinking
water?

a) 0 MPN/100 mL
b) 10 MPN/100 mL
c) 50 MPN/100 mL
d) 100 MPN/100 mL

Answer: a) 0 MPN/100 mL

120. What is the acceptable level of turbidity in treated wastewater?

a) Less than 2 NTU

b) Less than 5 NTU
c) Less than 10 NTU
d) Less than 15 NTU

Answer: a) Less than 2 NTU

121. What is the primary goal of water recycling?

a) To reduce the overall water demand

b) To increase water pollution
c) To increase the use of fresh water
d) To add contaminants to water

Answer: a) To reduce the overall water demand

122. Which of the following is a typical use of recycled water?

a) Drinking
b) Agricultural irrigation
c) Recreational swimming
d) All of the above

Answer: b) Agricultural irrigation

123. What is the first step in the water recycling process?

a) Filtration
b) Collection and transportation
c) Reverse osmosis
d) Chlorination

Answer: b) Collection and transportation

124. Which treatment process is commonly used in the recycling of wastewater?

a) Membrane filtration
b) Ultraviolet (UV) disinfection
c) Chemical coagulation
d) All of the above

Answer: d) All of the above

125. Which of the following is NOT a benefit of water reuse?

a) Reduces the strain on freshwater resources

b) Helps in controlling water pollution
c) Increases energy consumption
d) Reduces wastewater disposal costs

Answer: c) Increases energy consumption

126. In the context of water reuse, what is “non-potable reuse”?

a) Reuse of water for drinking purposes

b) Reuse of water for irrigation, industrial processes, and landscape irrigation
c) Reuse of water for recreational activities
d) Reuse of water for drinking and cooking

Answer: b) Reuse of water for irrigation, industrial processes, and landscape irrigation

127. What type of wastewater is most commonly treated and reused for irrigation?

a) Domestic wastewater
b) Industrial wastewater
c) Stormwater
d) All of the above

Answer: a) Domestic wastewater

128. The treatment process used to purify water by removing particles and microorganisms
is called:

a) Filtration
b) Sedimentation
c) Aeration
d) Coagulation

Answer: a) Filtration

129. Which of the following is the most common use of recycled water in urban areas?

a) Drinking water supply

b) Cooling in industrial processes
c) Recharging aquifers
d) Swimming pools

Answer: b) Cooling in industrial processes

130. The process of removing salt from seawater to make it suitable for reuse is called:

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

Answer: a) Reverse osmosis

131. Which of the following is a potential risk associated with the reuse of water?
a) Increased water quality
b) Increased risk of contamination if water is not treated properly
c) Improved nutrient levels
d) Reduced cost of water

Answer: b) Increased risk of contamination if water is not treated properly

132. Which of the following is an example of potable water reuse?

a) Using treated wastewater for irrigation

b) Using treated water in industrial cooling
c) Using treated water for drinking and cooking after advanced treatment
d) Using stormwater for landscaping

Answer: c) Using treated water for drinking and cooking after advanced treatment

133. Which of the following is a common method used for wastewater disinfection before
reuse?

a) Chlorination
b) UV light disinfection
c) Ozonation
d) All of the above

Answer: d) All of the above

134. What is "direct potable reuse"?

a) The reuse of treated water for non-drinking purposes

b) The immediate use of treated wastewater for drinking purposes
c) The reuse of untreated wastewater for irrigation
d) The reuse of water in industrial processes

Answer: b) The immediate use of treated wastewater for drinking purposes

135. Which of the following is a key challenge in the reuse of wastewater for drinking
purposes?

a) High energy consumption

b) Public perception and acceptance
c) The complexity of water filtration
d) Both b and c

Answer: d) Both b and c

136. Which of the following types of water can be recycled in wastewater treatment plants?

a) Greywater
b) Blackwater
c) Rainwater
d) All of the above

Answer: d) All of the above

137. What is greywater?

a) Water from toilets

b) Water from kitchens, bathrooms, and laundry
c) Water from industrial processes
d) Water from storm runoff

Answer: b) Water from kitchens, bathrooms, and laundry

138. Which of the following is NOT a typical method for treating wastewater?

a) Biological treatment
b) Chemical treatment
c) Physical treatment
d) Radiation treatment

Answer: d) Radiation treatment

139. Which of the following is the primary use of treated wastewater in urban areas?

a) Drinking water
b) Cooling water for industrial processes
c) Recreational water bodies
d) Irrigation and landscaping

Answer: d) Irrigation and landscaping

140. Which of the following parameters is essential for the success of water reuse
programs?

a) Water temperature
b) Contaminant levels
c) Cost of treatment
d) All of the above

Answer: d) All of the above

141. In the water reuse hierarchy, which of the following is considered the highest priority
for water recycling?
a) Agricultural irrigation
b) Industrial cooling
c) Potable reuse
d) Landscape irrigation

Answer: c) Potable reuse

142. Which treatment stage is typically used to remove organic material from wastewater?

a) Primary treatment
b) Secondary treatment
c) Tertiary treatment
d) All of the above

Answer: b) Secondary treatment

143. What is the main difference between "direct" and "indirect" potable reuse?

a) Direct reuse involves mixing treated wastewater directly into a drinking water supply, while
indirect involves storing it in an environmental buffer (e.g., an aquifer or reservoir) before reuse.
b) There is no difference between direct and indirect reuse.
c) Direct reuse requires no treatment, while indirect reuse requires multiple treatments.
d) Direct reuse is only for industrial use, while indirect reuse is for drinking water.

Answer: a) Direct reuse involves mixing treated wastewater directly into a drinking water
supply, while indirect involves storing it in an environmental buffer (e.g., an aquifer or reservoir)
before reuse.

144. Which of the following is an example of industrial water reuse?

a) Using treated wastewater for irrigation
b) Reusing cooling water in a factory
c) Recharging groundwater aquifers
d) Using treated water for drinking

Answer: b) Reusing cooling water in a factory

145. Which water treatment method is often used in the final stage of water reuse for
disinfection?

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

Answer: a) Chlorination

146. What is the major concern regarding the use of reclaimed water for agricultural
irrigation?

a) The presence of pathogens and harmful chemicals

b) The high cost of treatment
c) Water scarcity
d) High energy consumption

Answer: a) The presence of pathogens and harmful chemicals

147. What is an example of indirect potable reuse?

a) Treating wastewater and discharging it directly into drinking water systems

b) Storing treated wastewater in a reservoir before it is used as drinking water
c) Using treated wastewater for agricultural irrigation
d) Using treated wastewater for industrial purposes
Answer: b) Storing treated wastewater in a reservoir before it is used as drinking water

148. What is the typical lifespan of a water recycling system in a municipal treatment
plant?

a) 5-10 years
b) 10-20 years
c) 20-30 years
d) 30-50 years

Answer: c) 20-30 years

149. What type of water source is often used in water recycling programs for industrial
purposes?

a) Greywater
b) Treated effluent
c) Surface water
d) Groundwater

Answer: b) Treated effluent

150. What is one of the primary concerns regarding public acceptance of water reuse?

a) Cost of implementation
b) Taste and odor of recycled water
c) The complexity of treatment processes
d) The use of advanced technologies

Answer: b) Taste and odor of recycled water