If D.O. concentration falls down to zero in any natural drainage, it indicates the zone of__________________?

Related Mcqs:

1. The drainage area of a town is 12 hectares. Its 40% area is hard pavement ( K = 0.85), the 40% area is unpaved streets (K = 0.20) and the remaining is wooded areas (K = 0.15). Assuming the time of concentration for the areas as 30 minutes and using the formula Ps = 900/(t + 60) the maximum run off is__________________?

   A. 0.10 cumec
   B. 0.12 cumec
   C. 0.15 cumec
   D. 0.20 cumec

2. The most effective arrangement for diverting excess storm water into a natural drainage, is____________________?

   A. Leaping weir
   B. Overflow weir
   C. Siphon spill way
   D. None of these

3. 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

4. For drainage pipes in buildings the test applied before putting them to use, is__________________?

   A. Water test
   B. Smoke test
   C. Straightness test
   D. All the above

5. The rational formula for peak drainage discharge, was evolved by_________________?

   A. Fruhling
   B. Lloyd David
   C. Kuichling
   D. All of these

6. For house drainage minimum gradient is__________________?

   A. 1 in 60
   B. 1 in 80
   C. 1 in 10
   D. 1 in 400

7. When drainage to sewage ratio is 20, the peak dry weather flow is_______________?

   A. 20% of the design discharge
   B. Slightly less than 5% of the design discharge
   C. Slightly more than 5% of the design discharge
   D. None of these

8. In a city the ratio of the drainage to sewage is 20, the percentage discharge passing through non-monsoon periods, is_____________________?

   A. 5
   B. 10
   C. 15
   D. 20

9. A safety lamp when inserted in the upper portion of a manhole causes flames. It indicates the presence of______________?

   A. Carbondioxide gas
   B. Hydrogen sulphide gas
   C. Methane gas
   D. Petrol vapours

10. The algae dies out in the zone of_____________________?

    A. Degradation
    B. Active decomposition
    C. Recovery
    D. Cleaner water