Screening Of Bank Slope Wetland Substrate And Study On Treatment Effect Of Urban Polluted Rivers

With the acceleration of urbanization,the rapid increase of urban population,the huge consumption of natural resources,and the deterioration of the ecological environment have become more and more prominent,and the pollution of urban rivers has become increasingly serious.As a sewage treatment technology,constructed wetlands have been used by more and more researchers in recent years to improve the water quality of rivers and lakes and the ecological restoration of degraded natural wetlands.Compared with other sewage purification methods,the constructed wetland sewage treatment system has the advantages of less initial investment,convenient operation and maintenance,and remarkable sewage treatment effect.The core component of the constructed wetland wastewater treatment technology plays a key role in the removal of ammonia nitrogen,total nitrogen,total phosphorus and COD in the sewage.Therefore,the screening of wetland substrates is one of the key technologies to solve the sewage treatment of constructed wetlands.To study the research results of artificial wetland on water body repair at home and abroad,and to solve the shortcomings of large-scale artificial wetland treatment system,research and construct a new in-situ river water quality restoration technology system-multi-structure bank slope water purification system,this paper The selection of bank slope type wetland matrix in this water purification system and the treatment effect of wetland patches on urban polluted river water are mainly studied.According to the screening of different wetland substrates,the adsorption treatment effects of zeolite,ceramsite,red brick,anthracite and tire particles on total phosphorus and ammonia nitrogen were determined by isothermal adsorption test of single matrix.According to the preliminary test results obtained,the existing five kinds of substrates were divided into 12 groups for isothermal adsorption test of the combined substrates,and then 8 groups of 12 groups were selected to carry out batch adsorption tests of the combined substrates.The test finally obtained three groups of combined substrates with the best removal effect on ammonia nitrogen and total phosphorus.In the simulation test of the bank slope type wetland packing column,the preferred three kinds of combined substrates were used as the carrier for the test.The different hydraulic loads and different influent concentrations were used as different test conditions to investigate the treatment of sewage by three groups of combined substrates.The results show that the combined matrix containing a large proportion of zeolite has better effect on ammonia nitrogen and total nitrogen removal,and the combined matrix containing a larger proportion of ceramsite has better effect on total phosphorus removal.According to the results obtained from the simulation test of the bank slope type wetland packing column and the availability and environmental protection of the integrated matrix material,the combination of zeolite + anthracite + tire granule + red brick was selected as the combined matrix of the bank slope type wetland pilot test device Z1.Anthracite + ceramsite + zeolite is used as the combined matrix of the bank-type wetland pilot test device Z2.Through the test results,the following conclusions can be drawn: the test device Z1 has better treatment effect on TN and NH3-N in polluted river water,and the test device Z2 has better treatment effect on TP and COD in polluted river water than Z1,bank slope type wetland.It is more suitable to operate for 2-4 days as the hydraulic retention time.