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

The correct answer is: A. 20% of the design discharge.

The drainage to sewage ratio is the ratio of the volume of runoff to the volume of sewage. A drainage to sewage ratio of 20 means that for every 20 gallons of runoff, there is 1 gallon of sewage.

The peak dry weather flow is the maximum flow that a sewer system can handle during a dry weather period. It is usually calculated as a percentage of the design discharge, which is the maximum flow that the sewer system is designed to handle.

For a drainage to sewage ratio of 20, the peak dry weather flow is 20% of the design discharge. This is because the volume

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