| Rantional use of water resources and searching for environment friendly technology to promote sustainable economic and social development in our country have become more importantly. Compared with conventional techniques constructed wetlands which have many prominent features, such as high efficjency, low in vestment and low operation cost, low technology, good water quality, environment benefits is consistent which the requirements of new technology. Wastewater treatment in urban area of investment in environmental protection becomes more and more prominent. In the State Environmental.Protection Administration formulated the "Eleventh Five-Year" environmental investment planning, urban sewage treatment has been included in the 8 major focus of the project. However, according to statistics, China's sewage treatment rate is about 20% of all in the vast majority of small cities without sewage treatment is still discharged directly into water bodies, causing serious water pollution in China, the current municipal wastewater treatment technology is relatively mature modern two Stage biological treatment processes, land management and natural treatment systems, oxidation pond, the traditional activated sludge because of its infrastructure investment, higher operating costs and other shortcomings of investment in small towns are not very good promotion and application.This paper studies the towns-farming-field-landscape of four types of wetland wastewater treatment systems engineering and model.(1)Changsha Municipal Sewage (depth) in wetland projects:first, Changsha urban sewage treatment status and issues analysis, a practical green governance Changsha wastewater wetland project model that is:adhere to the River Control the main line, the implementation of "One River Four Rivers "(Changsha section of Xiangjiang River and Liuyang River, fishing knife river, River, Wei River, the five Jinjiang River basin) on both sides of the sewage treatment project of artificial wetlands. Biochemical treatment of the main city in the main, advanced treatment, supplemented by artificial wetlands; towns in rural areas dominated by wetland treatment, biological treatment, supplemented by-the main city sewage treatment plant tail water depth of constructed wetland treatment and water reuse and distributed processing in rural areas Based, distributed processing with focus on a combination of wetland management model. Meanwhile, foreign Lake sewage treatment plant constructed wetland system typical case illustrates the feasibility of the model:the use of artificial wetlands combined process model:the secondary settling tank-pond plants-an artificial wetland-two artificial wetlands-plants Tong-three artificial Wetlands-water, you can achieve the desired objectives.(2)Changsha breeding wetland wastewater treatment works:First, in Changsha, the problem of pollution and farming, puts forward the basic scheme:a scientific and rational planning, comprehensive management, low-carbon eco-farming, the development of rings through the economy, strengthen the effect of demonstration projects, to promote low-Carbon ecological farming, the government introduced policies to enhance breeding management, use of biogas technology is mature and reliable-aquaculture wastewater treatment wetland technology model works, as "animals-biogas-Wet-vegetable (fruit)" and adapt to the fish-based The "livestock-biogas-wet-fishing"and"low-carbon eco-farming, the development of rings through the economy " mode. Meanwhile, hundreds of Hunan culture should be the original pollution control pig propagation Co. case illustrates the typical pattern of the technical feasibility of:aquaculture wastewater treatment by biogas, methane production for the company, life energy, biogas residue and dried dung to do Organic fertilizer production of raw materials, biogas is mainly used for flowers, fruit trees, rice paddies, vegetable direct fertilization, some into the aeration tank, aeration tank through the degradation of natural wetlands into the artificial, artificial wetland treatment compliance, the part used for irrigation The company's green landscaped lawns and washing pig back to the water, the excess part of the emissions; in artificial wetland plants grown for green feed after harvest. This can achieve the desired objectives.(3)Changsha agricultural non-point source sewage control Wetland Ecological Engineering:First of Changsha farmland non-point source wastewater and control status of the investigation, made Changsha agricultural non-point source sewage control of ideas, strategy, planning, recommendations Changsha agricultural non-point source water control mode:Agricultural non-point source sewage-grid sedimentation-Cloth weir-one or more levels of wetlands-weir-water. Meanwhile, Lake Changsha Qingzhuhu Xingyue reservoir water purification wetland ecosystem engineering typical case illustrate the technical feasibility of the model:the use of "table flow wetland (A)-subsurface flow constructed wetlands (B) " three series+ water landscape (C) combined mode, the control of agricultural non-point source water, it can achieve the desired results. (4)Changsha landscape water pollution control Wetland Ecological Engineering: First of Changsha city status of wetland landscape pattern and water were analyzed, and the Changsha urban wetland landscape types are divided, the problems identified. Wetland landscape governance put forward ideas, strategies, plans, proposals, Changsha landscape water pollution control program:Root in the water purification system. Guide water purification system, overflow-type wetland purification system. Meanwhile, the pilot area beyond the river, in Changsha Meixi Lake Area control plan of the typical cases illustrate the technical feasibility of the model:the program by the amount of Meixi water balance analysis and calculations, and the surrounding Meixi Lake water analysis, through artificial Dragon King Kong Wetland water treatment, water supply 40,000 m3/d to May Lake, in order to ensure water quality in the lake.Research and analysis in four type, summed up the concrete to provide a sewage treatment ideas, strategies and programs. Analyzed and compared before and after treatment social and environmental benefits and economic impacts in a series of practical green Changsha Gezhongleixing wastewater treatment wetland project model; optimize wetland plants in constructed wetland in different seasons With planting programs; the development of low-carbon eco-farming, ring through the economy; ensure that when the wetland ecological resources development and sustainable development priorities. |
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