A. 1
B. 100
C. infinite
D. zero
Related Mcqs:
- In a BOD test, 1.0 ml of raw sewage was diluted to 100 ml and the dissolved oxygen concentration of diluted sample at the beginning was 6 ppm and it was 4 ppm at the end of 5 day incubation at 20°C. The BOD of raw sewage will be___________?
A. 100 ppm
B. 200 ppm
C. 300 ppm
D. 400 ppm - The correct relation between theoretical oxygen demand (TOD), Biochemical oxygen demand (BOD) and Chemical oxygen demand (COD) is given by_______________?
A. TOD>BOD>COD
B. TOD>COD>BOD
C. BOD>COD>TOD
D. COD>BOD>TOD - If Biochemical oxygen demand (BOD. of a town is 20000 kg/day and BOD per capita per day is 0.05 kg, then population equivalent of town is_________________?
A. 1000
B. 4000
C. 100000
D. 400000 - The ratio of 5 day BOD to ultimate BOD is about_______________?
A. 1/3
B. 2/3
C. 3/4
D. 1.0 - Dissolved oxygen in streams is______________?
A. maximum at noon
B. minimum at noon
C. maximum at midnight
D. same throughout the day - The minimum dissolved oxygen which should always be present in water in order to save the aquatic life is______________?
A. 1 ppm
B. 4 ppm
C. 10 ppm
D. 40 ppm - The dissolved oxygen level in natural unpolluted waters at normal temperature is found to be of the order of________________?
A. 1 mg/litre
B. 10 mg/litre
C. 100 mg/litre
D. 1000 mg/litre - Standard BOD is measured at________________?
A. 20°C – 1day
B. 25°C- 3day
C. 20°C – 5day
D. 30°C- 5day - The rate of BOD exerted at any time is_____________?
A. directly proportional to BOD satisfied
B. directly proportional to BOD remain-ing
C. inversely proportional to BOD satisfied
D. inversely proportional to BOD re-maining - The maximum efficiency of BOD removal is achieved in______________?
A. oxidation pond
B. oxidation ditch
C. aerated lagoons
D. trickling filters
