| Characters is the main recharge source of the tarim river,is also the general Mongolian autonomous prefecture of important water source In recent years,with the development of the characters in the industry and agriculture and human excessive exploitation and utilization of lake wetland,serious damage to the characters of the ecological environment,causing water quality deterioration,area of wetland degradation is serious Constructed wetland as a kind of simple and efficient ecological sewage treatment facilities of green environmental protection,in the process of heavy metal wastewater treatment applications.This study characters surface flow constructed wetland in the west bank as the research object,in April2019 on September intake of artificial wetland Outlet and artificial wetland internal all along the sampling points for continuous seven months of monitoring water concentrations of heavy metals,through comparative analysis of Mn Fe Cu with recent Cd Ni As a Cd of eight kinds of heavy metal water inlet and outlet of the average concentration change,quantitative analysis of constructed wetlands for the removal of heavy metals in water;And according to all water under the surface flow wetland system of heavy metal concentration variation along the river,the establishment of artificial wetland in heavy metal concentration along the water change model and combining with related data for a comprehensive evaluation on the operation condition of the constructed wetland,so as to accumulate experience for the construction of artificial wetland effluents basin,and provide scientific basis for the local ecological environment governance.(1)After continuous monitoring for 7 months,the average concentrations of Cr,As,Cu,Mn,Ni,Fe,Cd and Zn in the inlet water were 0.033 mg·L-1,0.031 mg·L-1,0.496 mg·L-1,0.7180 mg·L-1,0.038 mg·L-1,0.644 mg·L-1,0.003 mg·L-1,0.664 mg·L-1,respectively.The average concentration of heavy metals in the water outlet decreased to 0.019 mg·L-1,0.018 mg·L-1,0.234 mg·L-1,0.307 mg·L-1,0.021 mg·L-1,0.099mg·L-1,0.0017 mg·L-1,0.349 mg·L-1,respectively.The order of removal rate of heavy metals in the eight water bodies from high to low was as follows:The removal rates of:Mn>Fe>Cu>Zn>Cd>Ni>As>Cr,the removal rate reached54.14%,53.21%,51.99%,47.03%,42.1%,42.57%,41.04%,38.54%,respectively,indicati ng that the constructed wetland had a good removal effect on heavy metals in water..(2)From the point of view of removal rate,April to May(spring)is the initial stage of the constructed wetland operation,and the removal of heavy metals from the water body by the constructed wetland system has not reached the best effect.June to August(summer)is the peak period of the constructed wetland operation,in which the average removal rates of Mn and Zn increased by 20.84%and 13.55%respectively compared with the average removal rates in spring September to October(autumn)is the decline period for the operation of constructed wetlands,and the removal rate of heavy metals in water body is lower than that in summer.In general,the removal effect of constructed wetlands on heavy metals in water body is better in summer than in spring and autumn.(3)The concentration of heavy metals in the front section of the artificial wetland decreases the fastest,indicating that the heavy metals in the water are mainly removed at the removal efficiency of the middle wetland,and the concentration of heavy metals in the water fluctuates slightly at this stage,but still maintains the downward trend.In the rear section of the artificial wetland,the concentration of heavy metals in the water body is basically stable.Through the establishment of expon ential model,secondary pol yn om ial model and lin ear ization model,the relationship between the sampling points and the intake concentration of artificial wetland system is analyzed.The secondary pol yn om ial simulation equation fits the content of As?Ni?Cu?Zn and Cr,indicating that the decay of these five heavy metal elements is faster in the content of Cd?Fe?Mn in artificial wetland than other heavy metal elements.(4)The comprehensive evaluation score of the constructed wetland is 80.84,which shows that the constructed wetland is effective in operation,maintenance and supervision.From the analysis of each evaluation index,it can be seen that the constructed wetland has obvious effect in plant management,water quality monitoring,blockage management,equipment management,pollutant reduction rate and so on,which shows that the wetland plays an active role in engineering management,purifying water quality and improving ecosystem.During the operation of the wetland,there are some problems in water quality stability and wetland engineering maintenance. |
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