A. One hour
B. Two to three hours
C. Three to four hours
D. Six hours
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Related Mcqs:
- The pH value of fresh sewage is usually ______________________?
A. Equal to 7
B. More than 7
C. Less than 7
D. Equal to zero - Fresh sewage is generally_____________________?
A. Alkaline
B. Acidic
C. Highly decomposed
D. A source of objectionable odour - 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 - 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 - 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
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