1. There is a direct relation between water use and its required quality.
a) True
b) False
Explanation: There is a direct relation between water use and its required quality. The most demanding use can be considered as domestic water supply, which requires the satisfaction of the various quality criteria
2. _________ are constructed for water supply, electricity generation, recreation, irrigation and others.
a) Swimming pools
b) Ponds
c) Reservoirs
d) Tanks
Explanation: There are multiple uses assigned to water bodies, resulting in the necessity of satisfying diverse quality criteria. Reservoirs are constructed for water supply, electricity generation, etc.
3. What is the next step after water abstraction in wastewater treatment?
a) Supply to consumers
b) Treatment
c) Combine with stormwater
d) Supply to receiving body
Explanation: Initially, water is abstracted from the river, lake or water table and has a certain quality. Hence water is sent for treatment, where it undergoes transformation to be able to comply with intended uses.
4. Which of the following requires aesthetically pleasant water?
a) Domestic use
b) Industrial use
c) Irrigation
d) Aquaculture
Explanation: Industries need aesthetically pleasant water with low turbidity, colour, taste and odour, absence of macro-organisms. The water should be free from organisms harmful to health.
5. The addition of substances or energy forms that directly or indirectly alter the nature of the water body is called?
a) Water contamination
b) Water pollution
c) Sanitation
d) Water treatment
Explanation: Water pollution is the addition of substances or energy forms that directly or indirectly alter the nature of the water body in such a manner that negatively affects its legitimate uses.
6. What is the type of pollution where the pollutants reach the water body in points called?
a) Point-source pollution
b) Diffuse pollution
c) Point-source contamination
d) Diffuse contamination
Explanation: In point-source pollution, the pollutants reach the water body in points concentrated in space. Usually, the discharge of domestic and industrial wastewater generates point-source pollution
7. What percentage of solids does wastewater contain?
a) 0.5%
b) 5%
c) 0.1%
d) 1%
Explanation: Wastewater contains 99.9% water and 0.1% solids. The goal is to remove this 0.1% of solids. Wastewater is the water generated by industries and communities.
8. What is the growth of huge amounts of algae and other aquatic plants leading to the deterioration of the water quality called?
a) Eutrophication
b) Algae growth
c) Nitrification
d) Denitrification
Explanation: Eutrophication is the growth of huge amounts of algae and other aquatic plants leading to the deterioration of water quality. The untreated wastewater is rich in organic matter which demands oxygen
9. At higher temperatures, the amount of Dissolved Oxygen decreases.
a) True
b) False
Explanation: At higher temperatures, the amount of Dissolved Oxygen in the water decreases. This is because the rate of biochemical reactions increases as the temperature increases. This results in the depletion of Dissolved Oxygen.
10. The optimum temperature for bacterial activity is in what range?
a) 25-35 degree Celsius
b) 50 degree Celsius
c) 20 degree Celsius
d) 40 degree Celsius
Explanation: The optimum temperature for bacterial activity is 25-35 degree Celsius. Aerobic digestion and nitrification stop when the temperature increases up to 50 degree Celsius. When the temperature drops to 15 degree Celsius methane producing bacteria become inactive.