1. Surface flow constructed wetland
Surface flow wetland is very similar to surface flow land treatment system. The difference is:
(1) In surface flow wetland In the system, walls of a certain height are built around to maintain a certain water layer thickness (generally 10~30cm);
(2) Emergent plants (such as reeds, etc.) are planted in the wetland.
Distributing water to the surface of the wetland, the water flows forward in a push-flow manner on the surface of the wetland. During the flow process, it comes into contact with the biofilm of soil, plants and plant roots. Through physical, chemical and biological reactions, the sewage is obtained purified and streamed out at the terminal.
2. Subsurface flow artificial wetlands
The forms of subsurface flow artificial wetlands are divided into vertical flow subsurface flow constructed wetlands and horizontal flow subsurface flow constructed wetlands. Purify the incoming water by utilizing the characteristics of different flow patterns in the wetland. The river water purified by the underflow wetland can reach the surface water level III standard and then be discharged through the drainage system.
3. Vertical flow subsurface flow constructed wetland
In the vertical subsurface flow system, sewage flows longitudinally from the surface to the bottom of the bed. During the longitudinal flow process, the sewage passes through different patented media in turn. layer to achieve the purpose of purification. The vertical flow subsurface wetland has a complete water distribution system and water collection system. Its advantages are that it occupies a smaller area than other forms of wetlands and has high treatment efficiency. The entire system can be completely built underground, and green spaces can be built on the ground and used in conjunction with landscape planning.
4. Horizontal flow subsurface flow constructed wetland:
It is another form of subsurface flow wetland. The sewage flows from one end of the water inlet in the horizontal direction through sand, gravel, The medium and plant roots flow to one end of the water outlet to achieve purification purposes.
5. Ditch type constructed wetland:
Ditch type wetland bed includes plant system, media system and collection system. It mainly collects and processes non-point source pollution such as rainwater, and purifies rainwater and sewage through filtration, adsorption, and biochemistry. It is an effective means to control and protect water quality in small watersheds.
Function of wetland:
The function of wetland is multi-faceted. It can be used as a direct water source or to supplement groundwater. It can also effectively control floods and prevent soil desertification, and it can also retain water. sediments, toxic substances, nutrients, thereby improving environmental pollution; it can store carbon elements in the form of organic matter, reduce the greenhouse effect, protect the coast from wind and wave erosion, and provide a clean and convenient transportation method...
It is known as the "Kidney of the Earth" because it has so many beneficial functions. Wetlands are also a paradise for many plants and animals, especially waterfowl. At the same time, they provide humans with food (aquatic products, livestock products, grains), energy (water energy, peat, firewood), and raw materials (reeds, wood, medicinal plants). ) and tourist places are an important foundation for human survival and sustainable development.