ABSTRACT
The Rational Method has been generally employed in the design of systems utilizing centrifugal pumps, and the Probability Method has been employed for those systems which utilize semi-positive displacement pumps. In order to better understand the design of a pressure sewer system, it is usually advantageous to compare such a system with a standard gravity sewer design for the same project. The significance of the hydraulic gradient is that it provides the design engineer with head and flow conditions at any point in the pressure sewer system. Calculation of the hydraulic gradient is sequential in nature and must start at the furthest downstream point in the piping system. Decreasing the design flow as much as possible and increasing the overflow capacity is one method of attaining this goal. One advantage of dampening peak flows at intermediate pump stations is that design and operation of connections to the downstream forcemain are simpler.
