Experimental Study On Micro-Polluted River Water Treatment By Integrated Constructed Wetlands

The water pollution problem in our country is very prominent. The rivergovernance issues must be resolved. Constructed wetland sewage treatmenttechnology has the advantage of dealing with high efficiency operation and lowmaintenance costs, and applies a wide range, and has broad application prospects.Study to determine wetland constructed wetland basic design parameters, study ofdifferent fillers, temperature, hydraulic stay time of constructed wetland to removetreatment effect, seek compatible with the local wetland parameters and improve thewetland sewage treatment effect, artificial wetland in China promote the developmentof great significance.Lead to the northwest of Changchun City, Ecological Economic Zone ’ neweconomy ’ works too recycled water use, water quality protection test " project as thebasis, in Changchun City, Jilin Province Nong’an County Shunshanpu use ofreclaimed water test site, constructed by subsurface flow constructed wetland andtable flow constructed wetland consisting of complex wetland system, a one-yeartrial, analysis of finishing the test data, the following conclusions:（1）Constructed wetlands throughout the trial period, the average removal ofCOD, TP, and NH4+-N were16.12%,22.55%,34.68%. The constructed wetlandsystem purification works well.（2）Working conditions under the conditions of a integrated wetland system onthe removal efficiency of COD,TP,and NH4+-N were14.45%,18.55%,31.94%.Composite wetland system on the removal efficiency of COD, TP, and NH4+-N in thetwo conditions of the working conditions were11.71%,17.33%,18.42%.Constructed wetland systems in the three conditions of the working conditions ofCOD, TP, and NH4+-N removal efficiencies were24.75%,36.10%. Wetland systemof COD, TP and NH4+-N removal efficiency of working conditions one＞workingconditions two＞working conditions three.（3）Pollutant removal capacity from largest to smallest order of the integratedconstructed wetland> surface flow constructed wetlands> subsurface of constructedwetlands.（4）Temperature have a greater impact on the constructed wetland purifyingeffect, lower the temperature will lead to lower TP and NH4+-N removal rate,temperature changes have little effect on COD removal rate. （5）Matrix for the coarse sand subsurface flow constructed wetland, Unit2,COD, TP and NH4+-N removal capacity greater than3unit matrix for the gravelsubsurface flow constructed wetland.（6）Hydraulic retention time of less than0.82d, integrated wetland removal ofpollutants with the increase of the hydraulic retention time increased; hydraulicloading rate is greater than0.17m3/(m2d) under the conditions of wetlands onpollutants to In addition to the ability to increase with the decrease of the hydraulicloading. Therefore increase the hydraulic retention time, reducing the hydraulicloading is an important way to improve the constructed wetland purifying effect.（7） Generalize hydrogeological conditions of the experiment area, amathematical model using finite element method to solve the model, fitting the modelparameters, and test the groundwater level on the area of simulation and prediction ofwater. In the end of the predict time，experiment area groundwater level rise, thegroundwater hydraulic gradient is smaller. Simulation and prediction of engineeringinfiltration is282.42m3/d, paddy recharge is117.71m3/d, the excretion of the firstboundary is-3.66m3/d, the second boundary excretion-258.52m3/d, theequilibrium volume of154.67m3/d. Groundwater mainly vertical recharge, lateralexcretion. Integrated wetland water infiltration to groundwater has great influence onthe experiment area.