Research Of Planning And Design Of Constructed Wetland Water Purification Project In Panjin City Pang Xie Drainage

Wetland system related to human survival, reproduction and development, is one of the human living environment, but also the richest biodiversity ecological landscape in nature. On the one hand, wetlands provide a variety of resources forhuman life and production, on the other hand, wetlands play an irreplaceable role inregulating runoff, againsting floods, preventing drought, controling climate, controlling pollution, preventing degradation and landscaping. Wetland systemfunctioned as the “kidneys” of the earth, its environmental functions and economicbenefits are both well, and concerned all over the globe.With the large increase of population, land expansion of agriculture, economycontinues to grow as well as unreasonable development and unreasonable use of wetlands, the area of natural wetlands is dwindling, the function is declining gradually, the biological resources is reducing greatly, biodiversity is lossing gradually. Moreover, over-exploitation of wetland water resources, leading to water quality serious alkalization and lake area reduction. The long-term discharge of industrial andagricultural wastewater, domestic sewage, result in wetland water pollution is increasing, and seriously jeopardize the survival of wetland biological environment.In addition, the excessive felling of the forest resources, leading to siltation of rivers and lakes, soil erosion, and serious damage to wetland resources. In this paper, took pang xie drainage of Pan jin city as the research object, in view of pollutionaggravate of basin water, ruin of ecosystem structure and function and farmland of river beach.Took natural wetland system to deal with the water, in-depth understanding of the nature and environmental characteristics of the river pollution, selected the mostappropriate types of wetlands, preferred river planting, completed the recreational facilities along the river, and analyzed the environmental feasibility of the project, gotthe following conclusions:1) Main body of pang xie drainage should adopt the surface flow constructed wetlandsystem. Took full advantage of existing terrain and geomorphic characteristics of the river. Took the surface flow constructed wetland system as the core process. 2) Selected ceratophyllum demersum, Vallisneria, Hydrilla verticillata, Myriophyllum algae and other submerged plants, wild rice, high-quality reeds andother emergent plants as the plants of artificial wetlands to achieve the purification of polluted water.3) The wetlands construction projects could be effective in improving surface water environmental quality, the annual reduction of BOD5was7.31635t.4) Dredging depth was1m, dredging amount was13440m~3. Soil change amount: claydepth was0.4m, to do the impermeable layer, total5376m~3; freshloam was0.6m, took it as plants planted layer, total8064m~3; volcanic fill was0.3m, as microbial enrichment layer, total4032m~3.5) The amount of submerged plants:5strains/m~2, total67200strains; emergentplants:3strains/m~2, total40320strains.6) Green area of the construction were5536m~2, granite pavement sidewalk were2000m~2; granite pavement leisure Square were600m~2; and the construction hadrest pavilions6sets; gallery-style flower2sets; backdrop3sets; Sculpture(crabs, etc.)2; leisure stool7sets; lighting landscape lights and floor lamps75lights; fitness equipments16sets.7) The wetland construction projects mitigated the environmental pollution of surface water were effective in improving the ecological environment of the region.8) The wetland construction projects involved a wide range of moderate technicaldifficulty, in line with the overall planning requirements of the Liaohe protectedareas, and feasibility.