Septic Tank MCQ – Environmental Engineering

1. Septic tank is provided for

  1. setting of incoming sewage
  2. settle sludge digestion
  3. storage of digested sludge
  4. all these factors
Answer
Answer. d

2. Septic tank is a

  1. Setting tank
  2. Digestion tank
  3. Aeration tank

Which of the above is/are correct? Select the code for the correct answer from the options given below

  1. i only
  2. i and ii only
  3. i and iii only
  4. iii only
Answer
Answer. b

3. Soak pit is connected to

  1. manhole
  2. septic tank
  3. gulley trap
  4. nahani trap
Answer
Answer. b

4. The rate of accumulation of sludge in septic tanks is recommended as

  1. 30 litres/person/year
  2. 25 litres/person/year
  3. 25 litres/person/month
  4. 30 litres/person/month
Answer
Answer. a

5. From septic tank the effluents are discharged into

  1. Drainage
  2. Soak pit
  3. Oxidation pond
  4. Public sewer
Answer
Answer. b

6. Septic tank is a

  1. settling tank
  2. digestion tank
  3. both a and b
  4. none of the above
Answer
Answer. c

7. Septic tank is usually consists of brick wall in cement not less than

  1. 20 cm
  2. 100 cm
  3. 80 cm
  4. 200 cm
Answer
Answer. a

8. A chamber made of concrete, fibre glass, PVC or plastic, through which domestic waste water, Sewage flows for primary treatment is called

  1. septic tank
  2. drainage tank
  3. water harvesting tank
  4. pit latrine tank
Answer
Answer. a

9. Self cleaning velocity desired to be provided for septic tanks is

  1. 0.5 m/sec
  2. 0.75 m/sec
  3. 0.9 m/sec
  4. 1.05 m/sec
Answer
Answer. a

10. Septic tank involves

  1. sedimentation alone
  2. sedimentation as well as sludge digestion
  3. sludge digestion alone
  4. sewage aeration
Answer
Answer. b

11. A septic tank is

  1. Aerobic method of on-site sewage treatment
  2. Anaerobic method of on-site sewage treatment
  3. Physical method of water treatment
  4. Physico-chemical method of water treatment
Answer
Answer. b

12. Sludge from septic tank should be removed in

  1. 3 to 5 yrs
  2. 1 to 3 yrs
  3. 5 to 7 yrs
  4. none of the above
Answer
Answer. b

13. The detention period in septic tank is assumed as

  1. 8-10 hour
  2. 6-8 hour
  3. 12-36 hour
  4. 4-8 hour
Answer
Answer. c

14. The sewage treatment units, which work on anaerobic decomposition of organic matter, are

  1. Oxidation ponds
  2. Septic tanks
  3. Activated sludge plants
  4. b and c both
Answer
Answer. b

15. In septic tanks, decomposition of organic matter is done by

  1. anaerobic bacteria
  2. aerobic bacteria
  3. both types of bacteria
  4. none of the above
Answer
Answer. a

16. The gasses given out of a septic tank are

  1. CO, H2S, CH4
  2. CH4, O2, H2S
  3. CO2, NH3, CO
  4. CO2, CO, N2
Answer
Answer. a

17. Which kind of sewage treatment arrangement is ideal for a small colony of about 200 people?

  1. aqua privy
  2. soak well
  3. septic tank
  4. soak pit
Answer
Answer. c