A distribution pipe distributes the wastewater uniformly over the total width of the wetland. The supply is by gravity or pumping. The pipe is perforated with orifices (Ø 10 mm- 25 mm), distance between the orifices is approximately 10% of the cell width.
The distribution pipe is equipped with upright inspection pipes.
The inlet zone is covered with coarse gravel or rock.
Horizontal Subsurface Flow CW's: Inlet structures