Vertical Subsurface Flow CW's: Inlet structures
The distribution system distributes the wastewater evenly over the surface area of the reed bed. The wastewater is pumped 2 or 4 times a day in the top layer in short pumping cycles (5 to 10 minutes).
The pump capacity is calculated based on the total dynamic head (friction losses and vertical displacement) and the total lateral discharge rate of the distribution system.
The distribution pipes are PE pipes with a diameter ranging from 25 to 40 mm depending on the size of the wetland. Small orifices are drilled in these pipes, diameter of the orifices between 6 and 10 mm. The layout of the system should be based on a distribution pattern with one orifice per square meter.
The distribution pipes are covered with coarse gravel (8/16 or 8/32).