| This paper has three parts. In the first part, the run and management in initial stage of constructed wetland, the influence of operation parameters on the growth of plants, and the influence of the growth status of plants and of weeds on the removal of pollutants were studied to find out the key factor and some technology measures about constructed wetlands plant system optimizing and utilizing and systematic sewage treatment efficiency maximizing. Second was studied to affirm the design parameters necessary for water quality improvement project of Guanting Reservoir and the purification effect of wastewater of constructed wetland. The last part was performed to study on the design parameter necessary for constucted wetland running in the north area of China in winter, management maintenance and the purification effectt of wastewater of constructed wetland, which provide scientific basis for popularizing and applying constructed wetland in north of China.Results showed:It is important to control water level and hydraulic loading at the beginning of the constructed wetland systems start-up. Under the same hydraulic loading, the wetland with relatively better growing plants demonstrated higher pollutants removal efficiency than that with relatively worse growing plants, that is the pollutants removal efficiency was positively correlated to the growth status of plants. The presence of large quantities of weeds, those adapting drought weeds with superficial roots especially, reduced removal of contaminants in the wetland. The stem or leaf of reed and cattail in the artificial wetlands demonstrated good growth state and had obvious advantages in undercurrent type artificial wetland sewage disposal. Reeds and cattails are good plant varieties in the artificial wetland and kinds of very good high yield living resources for the output potential of them. As an artificial ecosystem, it is indispensable to relevantly manage and integrally utilize the plant in constructed wetlands.The subsurface flow constructed wetland system had comparatively obvious purification effect on the micro-polluted surface water of Guanting reservoir, as the hydraulic loading rate was 0.15~0.45m/d. The removal rates of CODMn were 20% and could reach to 60-70% even. The removal rates of CODMn showed certain seasonal variation, the rate in summer better than in autumn and the rate in spring similar to the one in autumn. The removal rates of NHU+-N kept high level during the running period that the average was above 60% and the maximum was nearly 100%. The removal rates of NH4+-N slowly increase seasonally from summer to spring eccept winter that the rate in summer was 59.4% and in spring was 77.1% .The removal rates lowered with the increase of hydraulic loading rate and the lowering of water temperature. The outflow of water in the system was 60% of water inflow, due to leakage, evaporation and plant transpiration.in cold winter, the subsurface flow wetland system had normal running, covered with different heat-insulation stuffs which greatly influenced on the treatment performance of the system. The removalrates of CODMn NH4+-N, BOD5, KN and TP were 15%, 50%, 65%, 25% and 35% respectively, as the hydraulic loading rate was 0.25~0.45m/d on an average, and the removal rates lowered with the increase of hydraulic loading rate and lowered remarkably when the hydraulic loading rate exceeded 0.4 m/d. The subsurface flow constructed wetland system had better purification effect on the micro-polluted surface water at low temperature in winter and very strong adaptive capacity in sewage disposal. So the subsurface flow constructed wetland has very great potentiality and very high using value.
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