The correct answer is: A. Equal to dry weather flow (DWF).
A separate sewer system is a type of sewer system that separates sanitary sewage from storm water. The design discharge for a separate sewer system is the amount of water that the system is designed to carry during dry weather conditions. This amount of water is typically equal to the dry weather flow (DWF), which is the average amount of water that is used in a building or area on a daily basis.
The other options are incorrect because they are too high. A design discharge of 2 Ã DWF or 3 Ã DWF would be too high for a separate sewer system, as this would result in the system being overdesigned and more expensive to build. A design discharge of 6 Ã DWF would be even higher and would result in the system being significantly overdesigned.
In conclusion, the correct answer is: A. Equal to dry weather flow (DWF).