Research On Constructed Wetlands Strengthen Nitrogen Removal For Tail Water Of Sewage Disposal Plants

Based on the quality index of a sewage treatment plant tail water of Qingyi River,especially at the total nitrogen(TN),which results in high eutrophication risk of receiving water.Considering the low carbon nitrogen ratio of tail water,how to remove the nitrogen in tail water is the most valuable and difficult topic in the field of denitrification.We adopt the external carbon source and sulfiur-based autotrophic horizontal subsurface-flow constructed wetlands in this article,and conduct real dynamic experiments to test the efficiency of scrubbing,and to study influential factors of sulfur-based autotrophic denitrification and microbial community structure.We also study the process of constructed wetlands and propose a revamping scheme and design.The production of our research is as follows.Effect of external carbon sources(corncob)on nitrogen removal in constructed wetlands treating tail water from sewage treatment plant.Experimental conditions is flooding height 10cm under matrix surface and HRT 2.5 d,The test operates under this condition.The results show that the total nitrogen at the initial stage of operation must be removed,the better effect with carbon source,the removal rate from high to low are gravel/volcano rock/zeolite with corncob carbon source>gravel with corncob carbon source>gravel without corncob carbon source.In the later period,roughly in 32-45 d,COD has a period of rapid rise,after which the total nitrogen removal removal rate decreased significantly.In the rising stage of COD,the solid carbon source of corn cob will be released.When the solid carbon source is consumed,there will not be enough carbon source for microbial growth in the following three groups of wetland system.Effect of sulfur autotrophic denitrification system on Nitrogen Removal in Constructed Wetlands Treating Tail Water from Sewage Treatment Plant.The result show that:sulfur/gravel/zeolite(volume ratio 1:1:1)and elemental sulfur/gravel/limestone(volume ratio of 1:1:1)in two groups of sulfur autotrophic systems,the optimum temperature is 25?-30?,When the temperature is low,Prolonging hydraulic retention time can improve the removal efficiency.sulfur/limestone/gravel is better.The influent concentration of NO3--N in the range of 10-30 mg/L,Removal rate of TN and NO3'-N gradually increased.Hydraulic retention time was 6-48 h.The removal rate of nitrate and total nitrogen reached more than ninety-five percent in matrix for sulfur/limestone/gravel and sulfor/zeolite/gravel.HRT<6 h,removal rate decreased significantly.Optimum temperature is 25?-30? in matrix for pyrites/zeolite/gravel,the influent concentration of NO3--N in the range of 10-30 mg/L,Removal rate of TN and NO3--N gradually increased.The optimal hydraulic retention time is 3 d.Study on microbial community structure in sulfur autotrophic system by Illumina MiSeq high throughput sequencing.The result show that 10 bacterial phyla in this system.Which accounted for about 40%of Proteobacteria,also found the anaerobic ammonium oxidation bacteria.Such as Planctomycetes.The dominant genera Thiobacillus,Sulfurimonas,Halothiobacillus and so on were found at the genus level.Study on technology of constructed wetland site Du Village Temple and existing problems from the level of plant configuration adjustment,optimization,enhanced biological clarification regulation pool transformation,vertical flow constructed wetland transformation in four aspects,combined with the application of sulfur autotrophic technology,put forward the technology improvement,renovation engineering design.Research on technology of constructed wetland and summarize the existing problems.Take the following measures,such as adjust the water level,optimize plant configuration,reforming biological regulation pool,reforming vertical flow constructed wetland.Combined with the application of sulfur autotrophic technology,put forward the technology improvement and improve the design of the project.