1. Surface flow wetland system is also called water surface wetland system. In the surface flow wetland system, sewage flows on the surface of the wetland, and the water level is shallow, mostly between 011 and 019 m. This system is closest to a natural wetland. The removal of most organic pollutants in sewage is accomplished by biofilms growing on the stems and poles of the underwater parts of plants. The advantage of this kind of wetland system is low investment, but the disadvantage is low processing capacity and poor sanitary conditions. In some areas of northern my country, it cannot operate normally due to the cold winter climate.
2. Underflow wetland system is also called percolation wetland system. In a hyporheic wetland system, sewage flows inside the wetland bed. Therefore, on the one hand, it can make full use of the biofilm growing on the surface of the substrate, the rich root system, and the interception of topsoil and substrate to improve its treatment effect and processing capacity; on the other hand, because the water flows under the surface, it has thermal insulation properties. It is good, the treatment effect is less affected by climate, and the sanitary conditions are better. It is a wetland treatment system that is currently widely researched and applied. However, the investment in this treatment system is higher than that of the surface flow system, and the removal effect of nitrogen and phosphorus is not as good as that of the surface flow wetland system.
3. The water flow in the vertical flow wetland system combines the characteristics of the surface flow wetland system and the subsurface flow wetland system. The water flow in the matrix bed is basically a vertical flow from top to bottom. , after the water flows through the bed, it is collected by the water collection pipe laid at the bottom of the water outlet and discharged from the treatment system. This type of system has higher infrastructure requirements and is more likely to breed mosquitoes and flies.