| The water pollution in our country is still serious,and the pollution mainly comes from two aspects of agriculture and life,which is difficult to deal with for small towns and non-point source pollution.Artificial wetland technology compared to traditional wastewater treatment process has the advantages of low operation cost and simple management.It has been widely used in the control of water pollution and non-point source pollution.Anammox under the condition of consuming little or no organic carbon source can also remove NH4+-N and NO2--N,which is regarded the most promising wastewater treatment technology.The study based on artificial wetland treatment plant in Jiulongpo Baishiyi Huahuiyuan Qinghe area as the research object,using stable isotope tracer experiments to measure the biological nitrogen contribution rate of anammox bacteria in the winter and summer of the wetland,using high-throughput sequencing technology to analyze microorganism in the winter and summer of the wetland.In NaHCO3-C as the carbon source and CH3COONa-C as carbon source under the condition of two kinds of anammox bacteria within the compound artificial wetland enrichment culture,to cultivate all kinds of data in the process of monitoring,the comparative study of two different conditions of anammox bacteria enrichment culture process and results.Under the condition of NaHCO3-C and CH3COONa-C as carbon source,two kinds of anammox bacteria was been enrichment culture in the compound artificial wetland,monitoring the training data in the process of comparative research on enrichment process and results under two different conditions of anammox.The results show that:(1)Anammox bacteria biological denitrification contribution experiments using the 15 N isotope labeling test in lateral undercurrent wetland show that when the nitrogen source pollutants are mainly NH4+-N and NO2--N,the anammox biological denitrification contribution rate in winter was 2.78%,the anammox biological denitrification contribution rate in summer was 29.38%,the anammox biological denitrification contribution rate in summer is significantly higher than that in winter,and all experiments show that the generation in gas and the loss in water of nitrogen element is about 10% in difference.(2)Microbial consortia structure analysis results of the horizontal subsurface flow wetlandshow that anammox bacteria was found both in winter and summer season.In winter season,only one genus was confirmed which belongs to Candidatus Brocadia,the relative abundance of which is 0.05%.In summer season,two kinds of genus was found which belongs to Candidatus Anammoxoglobus and Candidatus Brocadia,occupying 0.13% and 0.21%,respectively.Both winter and summer have the same kind of denitrification related microorganism,which abundance from high to low was denitrifying bacteria,nitrifying bacteria,ammonia oxidation bacteria,anammox bacteria.However,the abundance of each bacteria was not same in different seasons.The abundance of anammox bacteria in nitrogen cycle related microorganism was 0.31% and 1.55% in winter and summer,respectively.The dominant bacteria associated with nitrogen cycle was denitrification bacteria which accounted for 86.31% and 81.22%,respectively.The abundance of anammox bacteria in summer was and obviously higher than that of winter.(3)Under the conditions of autotrophic culture when the biofilm of the selected hybrid constructed wetland as inoculum and NaHCO3-C as the carbon source,the sludge particulates show clear red and have good settling performance,and showing obvious characteristics of anaerobic ammonia oxidation after 360 days of the enrichment culture.In addition,the system for culturing anaerobic ammonia oxidation bacteria is activated successfully in 184 days culture,which show obvious phenomenon of anaerobic ammonia oxidation,and the removal rate of NH4+-N and NO2-N exceed 60% and 95%,respectively.The specific value of ?NO2--N/?NH4+-N and ?NO3--N/?NH4+-N in the culture system are maintained at 1.59±0.11 and 0.23±0.05,respectively,after activating successfully the system.(4)Under the conditions of heterotrophic culture when the biofilm of the selected hybrid constructed wetland as inoculum and CH3COONa-C as the carbon source,the cultured sludge show a little red similar with the Anaerobic ammonia oxidation bacteria aggregates and contains a lot of sticky extracellular polymeric substance,have good settling performance after 360 days of the enrichment culture.Moreover,from 75 th day to 295 th days,the removal load and removal rate of NH4+-N increase gradually and removal rate of NH4+-N can reach to 33.79%,but the removal efficiency is always unstable in the whole experiment process.However,after 295 days of enrichment culture,the decreased amount of NH4+-N removal load is far lower than the theoretical calculated value according to anaerobic ammonia oxidation reaction when the load of NO2-N and NH4+-N are reduced by the same proportion.Therefore,the calculated results of the removal proportion of NO2-N,NH4+-N and NO3-N show that the denitrifying bacteria is the main microflora while the content of anaerobic ammonia oxidation bacteria may be very little in the system of enrichment culture,and the gradual increase of NH4+-N removal load may be a false phenomenon of anaerobic ammonia oxidation caused by some unknown reason. |
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