The Study Of Artificial Wetland Pollutant-Wiping Off Model And Enhancing Technology During Urbanization

Base on the existed wetland research domestic and international, this paper studied the factors that influenced biologic aerated filter and wetland treatment of contamination, the nitrogen and phosphorus removal mechanism and effect of Wenyu River water in Future Scientific and Technical Centre. The experiments include biologic aerated filter contamination treatment wetland matrix phosphorus removing and its performance wetland plant screening and phosphorus removing effect and wetland system strengthening and contamination removing test. The main results are showed as followings:(1) The main factors influencing the biologic aerated filter treatment effect are gas-water ratio and hydraulic loading. When the biologic aerated filter take the bio-ceramic as test fill when gas-water ratio is3:1and hydraulic loading is2.0m3(m2-h)(when the flow is15L/h, hydraulic residence time is0.2h), its removing effect to organics and ammonia nitrogen is the best, which are64.27%and55.36%receptively. At this time, the operation cost and power consumption is the lowest.(2) In the test research of constructed wetland matrix phosphorus removing and contamination treatment, steel-slag for phosphorus adsorption capacity of theory (G0) is88.07mg/kg and the coal slag (G0) is79.36mg/kg. With the increasing of pH value, phosphorus adsorption capacity of steel-slag and furnace slag is improving. If slag is in acidic or weak alkaline condition, the pH value is not obviously influence its adsorption capacity, but in alkaline condition the improving effect of pH value is significant.(3) In the test of constructed wetland plant screening and phosphorus removing effect, nitrogen and phosphorus removing effect of the cattail and reed are better than others. The biomass and nitrogen and phosphorus content of plants directly determined its nitrogen and phosphorus cumulative performance. By comparing the biomass and nitrogen cumulative performance of reed, water hyacinth, Alisma. cattail, Scirpus validus, lotus, the nitrogen content of cattail is the highest,15.3g/Kg, while water hyacinth is the second and lotus is the lowest,9.9g/kg; the phosphorus content of reed is the highest.7.2g/kg, while cattail is the second and Scirpus validus is the lowest,5.7g/kg.(4) In the test of separate constructed wetland system operation, the best operation water is85cm. the best hydraulic loading is1.1×10-2m3(m2-h) and the best pH value is8.5. The contamination removing effect of constructed wetland is proportional to the rising operation water level, but inversely proportional to inflow hydraulic loading. When the hydraulic loading is small, because of long stay of the hydraulic loading, the wetland forms an anaerobic environment, which is not beneficial to its removing effect. Conversely, if the hydraulic loading is too high, the removing effect is also decreasing because of the strong erosion. As organic contamination could be degraded by Aerobic and anaerobic microorganism, ammonia nitrogen must use aerobic nitrification before removing. COD/N has a little effect to the removing of COD in wetland system, and has a better effect to the removing of ammonia nitrogen. PH value has a big effect to nitrification.(5)The complex wetland system with both vertical and level undercurrent has a more steady effect to contamination treatment. The COD average remove rate of complex wetland is80.07%, the ammonia nitrogen average remove rate is71.85%, the overall remove rate of total nitrogen is not high, the average remove rate is73.91%, and the average remove rate of total phosphorus is75.64%. Under the same experimental conditions, the contamination treatment effect of vertical undercurrent wetland is better than level undercurrent wetland with10%. The vertical undercurrent constructed wetland has certain advantage in the contamination treatment.(6) Through the analysis of the DO distribution in the constructed wetland system, the problem of poor nitration can’t be totally solved when changing the concentration of the DO in the inlet water. The other methods must be used to change the DO distribution in the constructed wetland system to improve the effects of decontamination. The effects of decontamination is better when strengthen the technology of the whole constructed wetland than improving separate technology. This is mainly because the advantage of separate technology is used in different stages when dealing with different state of nitrogen contamination. The two technologies complement each other to achieve maximum removal of contamination.