If 2% solution of a sewage sample is incubated for 5 days at 20°C and depletion of oxygen was found to be 5 ppm, B.O.D. of the sewage is____________________?

Related Mcqs:

1. If a 2% solution of sewage sample is incubated for 5 days at 20°C and the dissolved oxygen depletion was found to be 8 mg/l. The BOD of the sewage is_________________?

   A. 100 mg/l
   B. 200 mg/l
   C. 300 mg/l
   D. 400 mg/l

2. If the depletion of oxygen is found to be 5 ppm after incubating a 2.5% solution of sewage sample for 5 days at 21°C, B.O.D. of the sewage is_____________________?

   A. 50 ppm
   B. 100 ppm
   C. 150 ppm
   D. 200 ppm

3. If the depletion of oxygen is found to be 2.5 mg/litre after incubating 2.5 ml of sewage diluted to 250 ml for 5 days at 20°C, B.O.D. of the sewage is_________________?

   A. 50 mg/l
   B. 100 mg/l
   C. 150 mg/l
   D. 250 mg/l

4. A five day B.O.D. at 15°C of the sewage of a town is 100 kg/day. If the 5 day B.O.D. per head at 15°C for standard sewage is 0.1 kg/day, the population equivalent is____________________?

   A. 100
   B. 1000
   C. 5000
   D. 10000

5. The ratio of maximum sewage flow to average sewage flow for trunk mains having diameters more than 1.25 m, is____________________?

   A. 1.5
   B. 2.0
   C. 3.0
   D. 4.0

6. 3.0 ml of raw sewage is diluted to 300 ml. The D.O. concentration of the diluted sample at the beginning of the test was 8 mg/l. After 5 day-incubation at 20°C, the D.O. concentration was 5 mg/l. The BOD of raw sewerage is______________________?

   A. 100 mg/l
   B. 200 mg/l
   C. 300 mg/l
   D. 400 mg/l

7. Which of the following pumps in used to pump sewage solids with liquid sewage without clogging the pump is ?

   A. Centrifugal pump
   B. Pneumatic ejector
   C. Reciprocating pump
   D. None of these

8. The ratio of maximum sewage flow to average sewage flow for mains up to 1 m in diameter, is___________________?

   A. 1.5
   B. 2.0
   C. 3.0
   D. 4.0

9. The density of population over 40 hectares is 250/hectare. If water supply demand per day is 200 litres and sewage discharge is 80% of water supply, the sewage flow in sewers of separate system, is_____________________?

   A. 0.05552 cumec
   B. 0.05554 cumec
   C. 0.05556 cumec
   D. 0.0556 cumec

10. If q is the average sewage flow from a city of population P, the maximum sewage flow______________?

    A. Q = [(4 + )/(18 + )] q
    B. Q = [(18 + P)/(4 + )] q
    C. Q = [(18 + )/(4 + )] q
    D. Q = [(5 + )/((15 + )] q