The filler medium plays an important role in wetland processes for sewage treatment.
At present, the wetlands treatment process makes wide use of grit sands, soil, gravels and other substrate fillers.
The investment is more efficient (Verlicchi and Zambello,2014 and Zhang et al., 2009), but the nitrogen and phosphorus removal efficiencies of these fillers are not ideal; therefore, experts have constantly developed new wetland fillers and carried out
different levels of tests.