Waste Water Engineering Questions and Answers - Systems of Waste and Sewage Disposal

1. What is night soil?
a) Soil containing urea
b) Human excreta
c) Animal excreta
d) Human excreta, animal excreta and urea

Answer: d
Explanation: Human excrement collected at night from buckets, cesspools, privies and sometimes used as manure is called night soil. The night soil consists of human excreta, animal excreta and urea originating at privies, water closets, urinals and stables.

2. Wastewater from different sources like bathrooms, kitchens and wash basins is called ______
a) Sewage
b) Garbage
c) Sullage
d) Discharge

Answer: c
Explanation: Dry wastes such as dry leaves, paper and grass are called garbage. Discharge is the outflow of water or wastewater. Sewage is the wastewater from various houses. Sullage is the wastewater from bathroom, kitchen, wash basins, etc.

3. Which of the following conditions is not suitable for the disposal of excreta or sewage?
a) The waste does not pollute the ground surface
b) It is not exposed to the atmosphere
c) It should be accessible for children
d) It does not give odour nuisance

Answer: c
Explanation: The place and criteria for the disposal of waste play a major role. It should be off the sight of the people so it doesn’t cause displease for the vision and it must not be accessible for children and household pets with respect to health aspects.

4. The system to collect night soil, garbage etc. in separate vessels or deposited in pools and pits is called _______
a) Conservancy system
b) Waste allocation system
c) Waste deposition system
d) Waste pit

Answer: a
Explanation: Conservancy system is an old system in which various types of wastes such as night soil, garbage, etc. are collected separately in vessels and deposited in pools or pits and then removed periodically once in 24 hours.

5. In urban cities like Bangalore, which of the water carriage system is used?
a) Separate system
b) Combined system
c) Partially combined system
d) Partially separate system

Answer: a
Explanation: Urban cities have a large area and high population, therefore water usage is more and sewage generated will also be more. Hence, a separate system to carry sewage and stormwater is necessary. Whereas in rural areas, precipitation will be absorbed by the ground and infiltered. Therefore only a little amount of precipitation forms storm. Hence the combined system is preferred.

6. Which of the following is an advantage of the conservancy system over water carriage system?
a) Labour force
b) Water consumption
c) Compact house design
d) Spread of epidemic

Answer: b
Explanation: In the conservancy system, compact house design is not possible, a large labour force is required and there is a spread of an epidemic. Hence, little water consumption is an advantage of the conservancy system over water carriage system.

7. The means of promoting hygiene through the prevention of human contact with the hazards of wastes especially feces is called ________
a) Hygiene control
b) Disease prevention
c) Sanitation
d) Hygiene

Answer: c
Explanation: Sanitation generally refers to hygiene by the prevention of wastes coming into human contact especially feces. The various measures taken to reduce the occurrence of diseases are called disease prevention.

8.The relatively clean wastewater from baths, sinks, washing machines and other kitchen appliances is called ________
a) Grey water
b) Black water
c) Yellow water
d) Wastewater

Answer: a
Explanation: Yellow water refers to the wastewater containing only feces. Black water is the wastewater from bathrooms and toilets. Wastewater generally refers to the water that cannot be used or water produced out of various uses.

9. The benefits of the society of managing human excreta are considerable, for public health as well as for the environment.
a) True
b) False

Answer: a
Explanation: For public health as well as for the environment the economic benefits of the society of managing human excreta are considerable. For every US$ 1 spent on sanitation, the estimated return to society is US$ 5.5.

10. The overall purpose of sanitation is to maintain the green environment alone.
a) True
b) False

Answer: b
Explanation: The overall purpose of sanitation is to provide a healthy environment for all and to provide safety, security and dignity for people when they defecate or urinate, not to just maintain a green environment alone.