ABSTRACT
Conventional sewers are designed for open channel, gravity flows. The enclosed pipe behaves like an open channel because the pipes are not com pletely filled with wastewater. The air above flow line is important and pre vents surcharging. Gravity is the motive force, pulling wastewater through a network of downward sloping pipes all the way to the treatment plant. Con ventional sewers work at atmospheric pressures; wastewater is not pressurized.
