A. When sewage is fresh
B. When diluting water has high dissolved oxygen content
C. When diluting water is used for water supply near the point of sewage disposed
D. When the diluting water is having flow currents
Related Mcqs:
- No treatment of the sewage is given if dilution factor is_____________?
A. Less than 150
B. Between 150 to 200
C. Between 200 to 300
D. More than 500 - 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 - 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 - 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 - 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 - For trunk sewers more than 1.25 m in diameter, the ratio of the maximum daily sewage flow to the average daily sewage flow is assumed________________?
A. 1.5
B. 2.0
C. 2.5
D. 3.0 - 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 - For sewer mains of 0.5 to 1 m diameter, the ratio of maximum daily sewage flow to the average daily sewage flow is assumed__________________?
A. 1.5
B. 2.0
C. 2.5
D. 3.0 - 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 - 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
