1. The application significance of constructed wetland sewage treatment technology

1.1 Regulate the urban climate and promote low-carbon life

Constructed wetland systems usually use multiple forms of conversion methods to convert water in the system into water vapor to increase regional air humidity, and then use rainfall to bring precipitation to the surrounding area, thereby regulating the regional climate. Relevant studies have shown that the evaporation of wetlands is usually 2~3 times that of the water surface. The key reason for the large evaporation of constructed wetlands is that the heat capacity of constructed wetlands can be continuously improved through naturally domesticated wetland aquatic organisms and artificially planted vegetation, thus achieving a large amount of water evaporation, and also making the wetland's ability to regulate climate greater than that of ordinary water surface. Constructed wetlands can not only increase the humidity of regional air, but also reduce regional temperature, thereby mitigating the heat island effect and improving air quality. Wetland vegetation exchanges carbon dioxide in the atmosphere through photosynthesis, balances water dynamics and carbon dioxide in the atmosphere, and effectively reduces the carbon dioxide content in the atmosphere, which is of great significance to regional economic development. Therefore, constructed wetlands can not only play a key role in regulating regional climate, but also develop a regional low-carbon economy.

1.2 Purify water resources and improve the utilization rate of water resources

At this stage, the phenomenon of eutrophication of water bodies affects the water system of various regions of our country to varying degrees, which is mainly caused by the enrichment of nitrogen and phosphorus in sewage. Surveys show that the effective removal rate of nitrogen and phosphorus from traditional sewage treatment modes is very low, resulting in the gradual enrichment of nitrogen and phosphorus after discharge, which in turn leads to eutrophication of surface water. The constructed wetland sewage treatment system can effectively purify the phosphorus and nitrogen in the sewage, and the wetland plants can effectively adsorb various substances contained in the sewage, especially phosphorus and nitrogen, and convert the adsorbed substances into trace elements that are conducive to plant growth, and can absorb the microorganisms of plant roots for decomposition. At present, the wetland system in some foreign regions can achieve good results in removing high levels of phosphorus and nitrogen from surface water. After testing, the purification rate of nitrogen and phosphorus is nearly 100%, realizing a new way to purify water sources for people.

2. Application analysis of sewage treatment technology in constructed wetlands

2.1 Sewage classification and treatment

In the traditional sewage treatment process, constructed wetlands are mainly for washing water, excrement rinsing water, planting water and aquaculture water for purification and treatment, in recent years have gradually developed towards urban sewage and industrial wastewater, as far as different types of sewage are concerned, their drainage and the pollutants contained in them are different, of which the content of nitrogen, phosphorus, carbon and toxic heavy metals is relatively different, so there is no need to use suitable substrates, microorganisms and aquatic plants to configure the treatment process for different types of sewage. Combined with the types and contents of toxic, inorganic and organic matter in sewage, it can be divided into anaerobic and aerobic biological treatment. The sewage treatment method can be divided into two treatment forms: centralized and decentralized, which can be directly connected to the urban sewage treatment system, mainly collecting and treating the sewage produced by households and farmers, which has the advantages of low construction cost and good treatment effect. The decentralized treatment is mainly for farmers and households to treat sewage, which effectively saves the capital investment in collection and transmission, and the small constructed wetland can also play the role of decorating the courtyard.

2.2 Combined use of sewage treatment technology

Although constructed wetlands can achieve good results in sewage treatment, their treatment cycle is long and the area is large, and it is difficult to meet the treatment requirements for large-displacement sewage treatment. For example, pond system treatment technology can be used to pre-treat phosphorus-rich water bodies; Membrane bioreactor is used as the pretreatment method for nitrogen-rich water bodies. The use of biological filters can be used as the pre-treatment method of rural domestic sewage, and the post-treatment can be carried out by stabilizing ponds. the activated sludge method is used to treat urban sewage in the early stage; The low-oxygen oxidation method is used to treat the polluted river water in the early stage, and the blockage of constructed wetlands can be treated by micro-aeration technology.

3. Strengthen the research on the sewage treatment mechanism of constructed wetlands

The sewage treatment mechanism of constructed wetlands is very complex and has a wide design range. At present, although some mechanisms have been preliminarily recognized, there are still many problems that need to be further studied and solved, such as more effective removal modes for organic and inorganic pollutants and metal pollutants contained in sewage; the joint effect on inorganic compounds, organic compounds and metal ions in the wetland system; The comprehensive role of microecosystems. It also includes the effects and effects on microorganisms, soil and vegetation.

4. Conclusion

In short, constructed wetlands are of great significance to protect the ecological environment with a sewage treatment system similar to nature, especially in the reuse of water resources. At present, our country mainly uses constructed wetland sewage treatment technology with simple technology, low operating cost and easy maintenance, but there are still certain limitations. Therefore, in order to realize the further development of constructed wetland technology, it is necessary to deeply explore the mechanism of constructed wetland purification pollutants, optimize the allocation of wetland vegetation and substrate, and then promote the ability of constructed wetland sewage treatment, and play a greater role in protecting the ecological environment and solving the water resource crisis.