复合型氧化沟工艺运行效能及氮去除规律研究

发布时间：2018-09-12 14:05

【摘要】：自2015年《水十条》和五大发展理念相继提出并成文以来,低碳、环保、绿色可持续发展依然成为国民经济发展中的核心问题,水污染治理、环境保护、水资源开发利用等问题纷纷被提到重要的议程上来。众所周知,由氮磷超标排放引起的水体富营养化一直是全球共同面临并亟待解决的环境问题,其中氮素在全球循环中的累积会对大气、水体甚至是人类自身健康产生不利的影响。随着社会经济的发展,我国整个污水处理行业已初成体系,各种污水处理工艺的应用也有相当的规模。但是,对于城市污水处理这一高能耗行业,合理能量配置、工艺参数优化以及新老技术交替等方面的研究仍然有着很重要的实践意义。氧化沟作为传统的活性污泥脱氮工艺有着其固有的特点和优势,本文以基于活性污泥-生物膜(IFAS)法的复合型氧化沟工艺为研究对象,分别研究探讨了其工艺特性和在不同调控因子下的运行效能,分析了污染物降解及SND过程作用机制,旨在为与之相关工艺的研究提供理论借鉴。并通过批次实验进一步探索讨论了生物脱氮机理,为生物脱氮新技术的创新和实践提供了不同思考。通过30多天的启动试验成功启动自行研制改造的复合型氧化沟装置,之后综合考虑分析了曝气量(G)、回流比(R)和水力负荷(Q)等不同参数因子对反应器运行效能优化的影响。通过整体分析系统脱氮除磷及SND效果,宜将曝气量(G)、回流比(R)和水力负荷(Q)分别调控为0.4m3/h、100%和0.55m3/m3·h进一步来优化调控效果。在G值为0.4 m3/h,底曝为50L/min,减速机转速为100r/min的条件下,装置取得了比较佳的运行效果,出水COD和NH_4~+-N的浓度分别为35.8mg/L、1.04mg/L,TN和TP的平均降解率为72.8%和68.4%,最终出水SS也保持在10mg/L以下。在利用复合装置处理实际生活污水的试验过程中,对N素的沿程降解和去除途径进行优化分析。生物脱氮过程中需维持适宜的C/N,本次试验为2.12~5.56,才能保证硝化反硝化的顺利进行。污水中N素的去向主要包括同化作用、传统硝化/反硝化作用、系统边界出水和SND等过程,通过优化控制临界DO值,可得最优SND%为42.7%,此时TN的去除率为71.7%。对两相填料区SND现象及脱氮机理进行探索分析。采用批次2k析因试验设计方法,进行异养硝化/好氧反硝化、自养反硝化的因控实验,并利用统计学分析方法对实验结果进行讨论。结果表明:新的微生物菌种对SND过程中N的损失作用非常有限(可忽略),试验中NH_4~+-N以及TIN的单位容积反应速率间显著性差异(P0.05)可解释为传统自养菌和异养菌的内源呼吸和内源反硝化综合作用的结果。通过化学计量学和细胞衰减动力学可以对N去除过程中的物质转化机制作更深入地阐释,并且可以进一步验证分析结果的准确性。通过整个试验过程及批次析因试验的探讨分析,认为复合型氧化沟两相填料区SND过程可解释为一种宏观或者微观的物理学作用现象。如何通过控制因子实现短程同步硝化反硝化和短程内源反硝化,并发挥其在提高脱氮效能和降低污泥产率等发面强大的优势,为污水处理新技术的革新和实践提供了思考。
[Abstract]:Since the "Water Ten Articles" and the five major development concepts were put forward and published in 2015, low carbon, environmental protection and green sustainable development have become the core issues in the national economic development. Water pollution control, environmental protection, water resources development and utilization have been put on the important agenda. Eutrophication has always been a common and urgent environmental problem in the world. The accumulation of nitrogen in the global cycle will have a negative impact on the atmosphere, water and even human health. With the development of social economy, the whole sewage treatment industry in China has already formed a system, and the application of various sewage treatment processes is quite similar. However, for the high energy-consuming industry of municipal sewage treatment, it is still of great practical significance to study the rational energy allocation, process parameters optimization and the alternation of new and old technologies. S) oxidation ditch process was studied. Its process characteristics and operation efficiency under different control factors were studied and discussed. The mechanism of pollutant degradation and SND process were analyzed. The purpose was to provide theoretical reference for the study of related process. The mechanism of biological denitrification was further explored and discussed through batch experiments. Innovation and practice of new biological denitrification technology provide different ideas. The self-developed and reformed compound oxidation ditch device was successfully started up after more than 30 days of start-up test. The effects of different parameters such as aeration rate (G), reflux ratio (R) and hydraulic load (Q) on the optimization of reactor performance were comprehensively considered and analyzed. The results of nitrogen and phosphorus removal and SND were optimized by adjusting aeration rate (G), reflux ratio (R) and hydraulic load (Q) to 0.4 m3/h, 100% and 0.55 m3/m3.h respectively. The average degradation rates of TN and TP were 72.8% and 68.4% respectively, and the final effluent SS was kept below 10 mg/L. In the experimental process of treating domestic sewage with composite equipment, the degradation and removal pathways of N were optimized and analyzed. Nitrification and denitrification can be guaranteed smoothly. Nitrification and denitrification in sewage mainly include assimilation, traditional nitrification/denitrification, effluent from system boundary and SND. By optimizing and controlling the critical DO value, the optimal SND% is 42.7%, and the removal rate of TN is 71.7%. The SND phenomenon and denitrification mechanism in two-phase packing area are explored and analyzed. The control experiments of heterotrophic nitrification/aerobic denitrification and autotrophic denitrification were carried out by means of 2K batch factorial design method, and the experimental results were discussed by statistical analysis. The results showed that the new microbial strains had very limited (negligible) effect on N loss in SND process, and the unit volume reaction rate of NH_4~+-N and TI N in the experiment was also discussed. The significant difference between rates (P 0.05) can be explained by the combination of endogenous respiration and endogenous denitrification of autotrophic bacteria and heterotrophic bacteria. Chemometrics and cell decay kinetics can be used to elucidate the mechanism of substance transformation in the process of N removal and to further verify the accuracy of the analysis results. The SND process in the two-phase packing area of the compound oxidation ditch can be interpreted as a macroscopic or microscopic physical phenomenon. How to realize short-range simultaneous nitrification and denitrification and short-range endogenous denitrification by controlling factors, and how to improve the efficiency of denitrification and reduce the sludge yield, etc. The strong advantages of the surface provide some thoughts for the innovation and practice of new sewage treatment technologies.
【学位授予单位】：重庆大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：X703

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