Rural Sewage Treatment Process And Microbial Community Structure Analysis Of Xinjiang

Through the investigation on water environment and water quality survey of rural areas in Xinjiang agricultural reclamation regions,the basic conditions for wastewater treatment design was determined.Combined with various sewage treatment process and engineering application conditions,OD?oxidation ditch?was selected to treat domestic sewage in order to achieve the unity of water purification and ecological cycle.Based on the objective of this work,the design of OD plant,operation factors?HRT,influent C/N,aeration?and systemic microbial population structure and distribution.Oxidation ditch technology had become a widely used process for domestic sewage treatment due to its high processing efficiency,simply operation and low capital cost.Oxidation ditch is a kind of activated sludge method.Activated sludge had become a key role in determining treatment efficiency on treatment systems.The community compositon and distribution of microorganisms in sludge were the most important factors affecting on removal of nitrogen and phosphorus.During the operation of sewage,the HRT?hydraulic retention time?,influent COD/NH₄⁺-N and aeration had the direct or indirect effects on the activity of microorganosms,which determines the final pollutant removal capacity of the wastewater treatment process.Hence,environmental changes in activated sludge had closely relationship with microbial metabolism.Only the process paramenters of above are at optimal operation coditions to ensure the highest activity of the sludge.Simultaneously,the complete analysis of microbial community distribution and function distribution in the activated sludge of the oxidation ditch is necessary.In the paper,based on the design and installation of OD,the simultaneous removal of organic carbon source,ammonia nitrogen and TP?total phosphorus?was performed.To analyze the oxidation ditch wastewater treatment process for a complete system,high-throughput sequencing technology and real-time fluorescence quantitative analysis?q-PCR?technology for the detection and analysis of the target gene was used to study the microbial population changes during the operation process of sewage treatment.In addition,due to the larger relatively proportion of energy consumption in wastewater treatment plants,the work was to study the dynamic changes and distribution of functional nitrogen-removing bacteria in different aeration conditions,which the functional nitrogen-removing bacteria contain Nitrobacteria?NOB?,Denitrifying bacteria?DNB?,Phosphorus bacteria?PAO?.It provides theoretical supports for the removal of nitrogen and phosphorus from domestic sewage.The results as following:?1?A laboratory-scale oxidation ditch device designed by CAD software,the specific dimensions are as follows:L×B×H=80 cm×20 cm×35 cm,the effective volume was 40 L,sewage treatment capacity was80 L/d.The best operating parameters in this experimental setup are:HRT=10 h,influent C/N=9/1,aeration=2 L/min.Under the operating condition,the removal of COD,NH₄⁺-N and TP is the best,and the removal rates are 90%,96%and 76%,respectively.?2?Through high through-put in sludge samples,Microbial Ecological Composition and Community Distribution of Activated Sludge in OD reactor was analysised.33 phylums,51 classes,424 geuns and other failed to match the sequence of the gene bank were detected in total.The micro-level of high-efficiency removal of nitrogen and phosphorus was revealed,which was rare in previous research.Through Miseq high-throughput analysis of oxidation ditch sludge,the structure composition of the activated sludge-rich species and the huge microbial functional distribution were revealed.Proteobacteria?Bacteroidetes?Planctomycetes and Chloroflexi are the main species of bacteria in the bacterial domain and play a central role in the biodegradation reactions in pollutants.Nitrifying bacteria,denitrifying bacteria and phosphorus-accumulating bacteria are powerful guarantees for nitrogen and phosphorus removal in the system.In addition,the presence of a portion of microorganisms may have an adverse effect on the efficiency of sewage treatment and water quality.?3?In order to explore the quantitative analysis of functional bacteria such as nitrifying bacteria,denitrifying bacteria,and phosphorus-accumulating bacteria under different aeration conditions and the dynamic trends of each genus in the process,the collected sludge samples were analyzed using real-time fluorescence quantitative analysis technology.The in situ detection analysis of the gene showed the following results:The decarburization performance of the system always maintains a high removal efficiency,maintaining at above 90%.With the decrease of aeration rate,the removal rate of NH₄⁺-N and TP changed.At 2.0 L/min,the nitrogen removal and dephosphorization performance of the reactor reached the highest,and the removal rate of NH₄⁺-N and TP was the highest.97%and 77%respectively,the concentration of NH₄⁺-N and TP in the effluent was 1.4 mg/L and 1.2 mg/L,respectively.The PCR results showed that the amount of AOB,NOB,DNB,and PAO strains was adjusted with the aeration amount and the range of variation was 3×10³¹×10⁴ copies/g,4×10⁶¹×10⁷ copies/g,respectively.,7×10⁶¹.2×10⁷copies/g,1.1×10⁴¹.8×10⁵ copies/g.Through results of this work,the optimum operation parameters on domestic sewage treatment with OD process was established.High-throughput analysis ensured researchers know the microscopic mechanism of removal of NH₄⁺-N and TP.The theoretical support for the practical application of the sewage was provided,there are reference signification for design of the similar sewage treatment process.