What are the types of constructed wetlands?

Subsurface wetland is the infiltration of sewage under the surface of filler, which can make full use of filler biofilm and plant roots to treat sewage, especially the removal ability of organic matter is outstanding. Surface-flow wetland means that sewage overflows on the surface of the filler, and most organic substances are purified by biofilm on the stems of plants below the water surface.

Vertical flow wetland sewage flows longitudinally from the surface of vertical flow constructed wetland to the bottom of filler. Different types of constructed wetlands have different removal effects on characteristic pollutants, and each has its own advantages and disadvantages.

According to the main forms of plants in wetlands, constructed wetlands can be divided into floating plant system, emergent plant system and submerged plant system. At present, submerged plant system is still in the experimental stage, and floating plant system is mainly used in biological oxidation tank. Generally speaking, constructed wetlands are emergent plant systems.