190.  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.

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191.  Sewer pipes need be checked for
A. minimum flow
B. maximum flow
C. both A and B
D. none of these.

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192.  The design period of sewage treatment works in normally
A. 5-10 years
B. 15-20 years
C. 30-40 years
D. 40-50 years.

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193. 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
C.2.5
D. 3.0.

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194. 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
C.25
D.3

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195. The ratio of minimum hourly flow to the average flow of sewage is
A. 1/4
B. 1/3
C. 1/2
D. 3/4.

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196.  Sewer pipes are designed for maximum discharge with 25% to 33% vacant cross-sectional area for
A. unexpected large scale infiltration of stream water
B. unexpected increase in the population
C. under estimates of maximum and average flows
D. All of the above.

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