| The urban landscape water quality has received much attention in recent years. Itcan not only provide people with a place for leisure travel, but also improve the regionalecological environment. With the surge in urban population, human activity has causedserious influence on urban landscape water. The area of the urban landscape water isreducing year by year, ecosystem is degenerating, function of urban landscape waterslashed. As a result, it is extremely important to treat the urban landscape water.This study was based on the characteristics of the landscape water and constructedwetlands in north China, and it took Xi’an Chanba Yanming lake for example to make atest in lab and set up constructed wetland demonstration project. The test used thecombination process of surface flow-undercurrent constructed wetland, and mixedmatrix made from terminal sediment of water plant and kaolin to treat the water,furthermore, removal efficiencies of pollutants such as TN, TP, COD, NH3-N, SS, Chl-awere analyzed, which provide theoretical basis and design reference for demonstrationproject.The results showed that:(1) Yanming lake was seriously contaminated, its heavily polluted area TN, TP,CODCr, NH3-N, SS, Chl-a average values were3.9mg/L,1.3mg/L,43.2mg/L,3.6mg/L,31.5mg/L,24.4×10-3mg/L, so the water need to be processed as early as possible.(2) The modified ceramsite matrix made from terminal sediment of water plant and kaolin has good physical and chemical properties, which could enhance thedecontamination ability of constructed wetlands and solve the sludge handling problems,to achieve the purpose of using waste to treat waste.(3) Test results showed that the surface flow area have a good removal forCODCr,Chl-a and SS, which could reduce the risk of substrate clogging in the undercurrent area.When the water passed by undercurrent area, the removal rate of CODCr, Chl-a and SSwere respectively up to more than80%,99%, and90%.The removal of TN, TP, NH3-Nwere mainly in the undercurrent area and the average removal rate were63.7%,65.9%and79.9%respectively. The CODCrconcentration of inflow had a greater influence onthe change of TN and TP removal, and the change of TN and TP had less influence onthe removal of CODCr. HRT is set for1to3d, and with the increase of HRT, theremoval rate of CODCr, TN and TP also increased; when HRT is between1to2d, theincrease speed is faster, and it is relatively slower when HRT is between2to3d.(4) On the basis of long-term monitoring and test in the laboratory, the constructedwetland treatment system, including surface flow, undercurrent and water fall wereultimately determined as the process flow of demonstration project. |
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