Waste Water Engineering Multiple Choice Questions on “Disinfection Process – 1”.
1. Which is the common indicator organism used in the evaluation of drinking water?
a) E. coli
b) Fecal coliform
c) Total coliform
d) Algae
Answer: c
Clarification: The most common indicator organism used in the evaluation of drinking water is Total Coliform (TC), unless there is a reason to focus on a specific pathogen.
2. Which is the common indicator organism used in the evaluation of wastewater?
a) Fecal coliform
b) Total coliform
c) E. coli
d) Algae
Answer: a
Clarification: The most common indicator organism for wastewater evaluation is fecal coliform but there has been discussion regarding the use of Escherichia coli (E. coli) or Total Coliform.
3. Surface water contains approximately 1,000 times more indicator organisms than domestic wastewater.
a) True
b) False
Answer: b
Clarification: Domestic wastewater contains approximately 1,000 times more indicator organisms than typical surface water, understanding wastewater disinfection will make it easier to understand water disinfection.
4. Which year was the Safe Drinking Water Act passed?
a) 1990
b) 1992
c) 1994
d) 1996
Answer: d
Clarification: Amendments to the Safe Drinking Water Act in 1996 mandate the development of regulations to require disinfection of groundwater as necessary.
5. The solution to pollution is _______
a) Reuse
b) Dilution
c) Detection
d) Cleaning
Answer: b
Clarification: The last 100 years have brought significant environmental advances. At the beginning of the 20th Century, water and wastewater were treated by one principle, “the solution to pollution is dilution.”
6. ________ means the deactivation or killing of pathogens.
a) Reduction
b) Disinfection
c) Oxidation
d) Pyrolysis
Answer: b
Clarification: Water disinfection means the removal, deactivation or killing of pathogenic micro-organisms. Micro-organisms are destroyed or deactivated, resulting in termination of growth and production.
7. Sterilization is a process related to disinfection
a) True
b) False
Answer: a
Clarification: Sterilization is a process related to disinfection. However, during the sterilization process, all present micro-organisms are killed, both harmful and harmless micro-organisms.
8. Which of the following is not a chemical disinfectant?
a) UV
b) Ozone
c) Chlorine
d) Bromine
Answer: a
Clarification: There are various physical, chemical and biological disinfectants used for disinfection process. Chemical disinfectants are ozone, chlorine, bromine, ammonium and hydrogen acids etc.
9. Which of the following is not a physical disinfection means?
a) Heat
b) Sound
c) Metals
d) UV
Answer: c
Clarification: For physical disinfection of water, means like heat, sound, light (UV), electronic radiations and gamma rays can be used.
10. ________ is the process where all the living micro-organisms, including bacterial spores are killed.
a) Disinfection
b) Sterilization
c) Incineration
d) Pyrolysis
Answer: b
Clarification: Sterilization can be achieved by physical, chemical and physiochemical means. Chemicals used as sterilizing agents are called chemisterilants.
11. Which of the following means cannot be used for sterilisation?
a) Physical
b) Chemical
c) Physiochemical
d) Biological
Answer: d
Clarification: There are various means used for the process of sterilization. They are physical, chemical and physiochemical. Biological means cannot be usually used for sterilization.
12. ______ is the process of elimination of most pathogenic micro-organisms.
a) Pyrolysis
b) Incineration
c) Disinfection
d) Sterilisation
Answer: c
Clarification: Chemicals used as sterilizing agents are called chemisterilants. Disinfection can be achieved by physical or chemical methods. Chemicals used in disinfection are called disinfectant.
13. What is the chemical or mechanical cleansing process called?
a) Sterilization
b) Disinfection
c) Decontamination
d) Sanitization
Answer: d
Clarification: Sanitization is the process of chemical or mechanical cleansing, applicable in public health systems. Usually used by the food industry. It reduces microbes on eating utensils to safe, acceptable levels for public health.