The amount of oxygen consumed by the aerobic bacterias which cause the aerobic biological decomposition of sewage, is known_________________?

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. 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____________________?

   A. 200 ppm B. 225 ppm C. 250 ppm D. None of these...

5. To maintain aerobic biological activity, the moisture content of the compost mass should be about_________________?

   A. 45 % B. 50 % C. 55 % D. 60 %...

6. Pathogens (or pathogenic bacterias) in water may cause___________________?

   A. Typhoid B. Cholera C. Dysentery D. All the above...

7. The sewage treatment units in which anaerobic decomposition of organic matter is used, are called________________?

   A. Imhoff tanks B. Trickling filters C. Sludge sedimentation tanks D. None of these...

8. Assertion A. : Discharging the effluents from the oxidation ponds just up stream of lakes or reservoirs is undesirable. Reason (R) : The discharged algae get settled in the reservoirs and cause anaerobic decomposition and other water qualities_________________?

   A. Both A and R are true and R is the correct explanation of A B. Both A and R are true but R is not a correct explanation of A C. A is true but R is false D. A is false but R is true...

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...