Engineering Experiment For Treating Polluted River Through Constructed Wetland

Constructed wetland,which was a kind of relatively complete ecosystem,was an emerging technology for wastewater treatment.It had many advantages such as higher efficiency, lower cost of investment,operation and maintenance,wide application,and great capability of resisting impact and load.It was being researched,developed,and applied in wastewater treatment.However,for the constructed wetland could easily be affected by a given region, much deficiency still existed in the river training.Especially,the purification mechanism of wetland was still unknown,and the hydraulics was complex.Moreover,it was lack of comparatively standard designing parameters and operational experiences.Therefore, combined with the hydrology and water quality of polluted river,the typical climate and geography in the area of plateau lake in Yunnan Province,and relied on the composite constructed wetland project of Maliao river,and through successive monitoring of operational conditions in a long-term,our research analyzed the purification efficiency of the project,and provided the references for the in-flow river treatment of plateau lake.The main content was as follows:(1)The paper reviewed the research and application on the river treatment home and board, prospected the technique for river treatment,and carried out the systemic analysis about purification and decontamination mechanism of wetland.(2)Based on the types and polluted characteristics of river in the area of plateau lake in Yunnan province,the research had provided the feasibility and applicability of constructed wetland for the river treatment.(3)Combined with the environmental situation and water quality status of the project's area, the paper had analyzed the project's test conditions and provided with the engineering design scheme of "Grid for Conservancy Trash+Settling Tank with Bioenhanced Treatment +Subsurface Flow Wetland+Surface Flow Wetland" for Maliao river treatment. (4)Through tracking monitoring of the project,the paper studied the project's purification capacity,and contrastively analyzed,the efficiency of plant absorption by different plant configuration in different treatment stages.The result of the test indicated:the purification efficiency was better,various indexes of water quality's consistency were decreased from inlet to outlet.Analyzed from the angle of removing surface load from pollutants,the average load of the whole wetland system were TN 0.72g/m²Â·d,NH₃-N 0.22g/m²Â·d,TP 0.06g/m²Â·d,COD_Mn1.23g/m²Â·d,COD 8.54g/m²Â·d,BOD₅ 0.82g/m²Â·d,DO 1.22g/m²Â·d,SS 219.74g/m²Â·d.(5)Combined with the characteristics of inlake' rivers and climatic in Yunnan province,and set up the engineering case,the paper put forward the design parameter of wetland engineering,and analyzed the optimum engineering parameters by verification.(6)Based on the characteristics of the plant in Yunnan province,the research had explored the screening of plants,breeding,management and their effects in the wetland.In addition, the paper put forward the optimum technological combination of wetland according to local and hydrodynamic conditions,which based on some factors such as the properties of wastewater and the conditions of project's region,etc.