Shangmo Village Model of Constructed Wetland
"The artificial wetland in Shangmo Village is just a model, with an investment of more than 700,000 yuan, an annual operating cost of not more than 30,000 yuan, a service life of 20 years, and only 1 dime per ton of water treatment. Such an artificial wetland is along the banks of the Luan River. It can be used for sewage treatment in natural villages and towns. The reeds on the bed are a kind of aquatic plants with high survival rate, strong water resistance, long growth period, beautiful and economic value. They can be removed by the root system of the reeds and sedimentation and adsorption. The nitrogen, phosphorus, organic matter and suspended matter in the sewage can achieve the purpose of sewage purification. At the same time, reed can also become a green landscape. At present, there are many models and technologies of artificial wetland. "Plant Nutrition and Resources of Beijing Academy of Agriculture and Forestry Zhang Chengjun, associate researcher at the institute, said.
According to the bulletin of the Beijing Municipal Bureau of Water Affairs, Beijing is a resource-intensive and severely water-scarce region, one of 111 extremely poor water cities, and one of the three cities with the fastest decline in water inventory in the country. The per capita water resources are less than 300 cubic meters, which is 1/30 of the world's per capita water resources and 1/8 of the national per capita water resources, which is far below the international water shortage limit of 1,000 cubic meters per capita. Water resources are scarce, and the regeneration and recycling of water is even more urgent and important. Reclaimed water, also known as reclaimed water, refers to water that, after proper treatment, meets certain water quality targets, meets certain usage requirements, and can be used beneficially. Compared with desalination and cross-basin water transfer, reclaimed water has obvious advantages. From an economic point of view, the cost of recycled water is the lowest. From an environmental point of view, wastewater recycling helps improve the ecological environment and achieve a virtuous cycle of water ecology.
At present, scientists from various countries are vigorously studying sewage treatment technology, constructing sewage treatment plants and constructing artificial wetlands, so that human beings can live in a homeland with beautiful scenery and beautiful environment.
Looking at artificial wetlands at home and abroad
Let's look at home and abroad and learn about artificial wetlands.
Artificial wetlands can be divided into three types of wetlands: surface flow, horizontal underflow, and vertical underflow according to the system's water distribution method or water flow method. Compared with artificial wetlands with horizontal and vertical subsurface flow, surface-flow wetlands have the advantages of low investment, low operating costs, and easy operation. In summer, it is easy to breed mosquitoes and flies, which will produce odor and affect the wetland environment.
Research on constructed wetlands in China began in the "July Five" period. Since the late 1980s, Tianjin, Beijing, Shenzhen, and Shanghai have successively constructed artificial wetland wastewater treatment projects, and conducted a comparatively systematic study of the laws and mechanisms of wastewater treatment. Since the beginning of the 21st century, China has made great progress in artificial wetland treatment technology and engineering applications. Currently, dozens of cities have conducted research on artificial wetlands, and hundreds of artificial wetlands have been put into operation. Sewage treatment capacity ranges from 100,000 cubic meters to 110,000 cubic meters per day. It is used in domestic sewage, municipal sewage, landscape river and lake water, industrial sewage, mining sewage and other treatments, and has contributed to protecting water resources.
In recent years, China has made great progress in the research and engineering application of horizontal and vertical subsurface constructed wetlands. For example, the Shenyang Academy of Environmental Sciences has carried out unit application research and engineering demonstration of horizontal subsurface constructed wetland technology according to the climatic characteristics of the northern region. The sewage ecological treatment project of the Shenyang World Garden Fair in 2006, the sewage treatment capacity is 1,000 cubic meters per day, which not only purifies the domestic sewage in the park, but also reuses reclaimed water for fountains, watering flowers and landscape water systems. Shenzhen Institute of Environmental Sciences uses vertical flow or composite vertical flow constructed wetland technology for comprehensive research to form integrated technologies suitable for comprehensive water environment management in the southern region. Dozens of artificial wetlands have been designed and operated in Shenzhen, Guangzhou and other areas. Treatment of residential and urban sewage, municipal sewage, landscape rivers and lakes. The water quality purification project of Honghu artificial wetland system, which was designed and constructed in early 1999, has a sewage treatment capacity of 1,000 cubic meters per day, and applies vertical flow artificial wetland water purification technology to Honghu Lake pollution control. The Shanghai Academy of Environmental Sciences uses vertical-scale constructed wetland technologies of different scales and is applied to 9 domestic sewage treatment projects in rural areas of Shanghai.
At present, the research and application of artificial wetlands in China are in the ascendant. The research and construction of artificial wetlands are also highly valued abroad. In 1974, West Germany built its first artificial wetland. North America built 174 constructed wetlands in the 1970s and conducted extensive tests on them. In the late 1980s and early 1990s, the United States held a number of seminars on artificial wetlands, and there were 4 international seminars. It summarized the experiences of artificial wetlands in various countries and put forward related theories and reference design parameters. According to statistics, as of 2006, there were more than 10,000 constructed wetlands in Europe and more than 20,000 constructed wetlands in North America, and more and more constructed wetlands were also put into operation in Asia, Oceania, and Latin America.
At present, two-thirds of wetlands in North America are surface-flow constructed wetlands, half of which are natural wetlands. Submerged constructed wetlands are more commonly used in Europe, especially in some countries in Eastern Europe. Reeds, calamus, cattail and other wetland plants are planted in the wetland system. In order to ensure the underflow, most of the gravel is used as filler. Europe tends to use such systems for secondary treatment of domestic sewage in communities with a population of nearly 1,000, North America tends to intensively treat domestic sewage in areas with large populations, and Australia and South Africa are used to treat various types of sewage.
