Nanfei River Demonstration And Pollution Characteristics Of The Sediment In The Prevention And Control Measures

As a long time not to clean up,Nanfeihe sediment deposition serious, not only for the city’s flood control and drainage as a barrier, but also to render eutrophication.To better understand the dredging of river pollution situation, dredging effect and How control pollution Nanfeihe after dredging.Under the state water pollution control and treatment of major science and technology topics relying(issue:2011ZX07303-002). In this paper, the distribution of contaminated sediment Nanfeihe characteristics, sediment contamination assessment, risk assessment, release characteristics, dredging study the impact of these specific issues.1)In a demonstration to take 10 representative sampling point, the nitrogen content in sediment samples between 997.92mg/kg-1898.38mg/kg, with an average of 1150.82mg/kg; sediment phosphorus content 662.6mg/kg between-1384.3mg/kg, with an average of 777.70mg/kg; sediment organic matter content of the soil in the proportion between the average of 4.82%-6.78% to 4.99%. With increasing depth of sampling, the content of nitrogen and phosphorus were significant downward trend. Organic and organic nitrogen index evaluation showed the sample reaches are varying degrees of organic nitrogen pollution and organic contamination. Change the value of ten sample points Zn 305.2-1158.3mg/kg, with an average of 519.53mg/kg, the value of Pb changes 427.7-98.6mg/kg, with an average of 51.63mg/kg, a value of variation 37.2 Cr-128.4mg/kg, with an average of 88.05mg/kg, the cumulative index rating and the potential hazards and pollution by heavy metals coefficient method, the upper reaches of Pb and Cr pollution is almost zero, ancient bridge following moderate and mild Cr Pb pollution pollution; sampling reach Zn pollution is more serious.2)Environmental factors on sediment phosphorus adsorption-desorption of research experiments drawn:As the temperature increases, the release of nitrogen and phosphorus showed a positive correlation with temperature, COD released within a certain range of temperature rise and showed a positive correlation above a certain temperature emission limit negative correlation with temperature. The release rate of phosphorus in sediment disturbance intensity increases with increased phosphorus release rate under high frequency oscillation rate is higher than the rate of release of low volatility and no shock when. Nitrogen and COD content is positively correlated with the disturbance frequency. effect of pH on the rate of speed the release of nitrogen and phosphorus COD, was "U" shaped curve distribution.3) comparing before and after dredging contaminants can be drawn:reduce the sediment dredging project in TP, TN and organic matter, to a certain extent within the control of the nitrogen and phosphorus pollution, contamination of organic nitrogen and organic pollution significantly improved, organic pollution can be effectively controlled by dredging. But dredging as a single control measures failed to fundamentally change the status of water quality pollution Nanfeihe. Dredging mud sink to the bottom table can effectively reduce heavy metals Pb, Zn and Cr pollution, dredging sediment after removal of Pb maximum of 58.5%, the average removal rate of 42.9%; maximum removal rate was 86.4% Zn, average removal rate of 51.2%; maximum average of 48.0% Cr law, the average removal rate 32.2%, good control of heavy metal pollution risks.Finally, this paper findings and dredging segment features, given the river sediment dredging and pollution control measures and long-term management of the proposed measures.