CSTR中亚硝化颗粒污泥性能调控影响研究

发布时间：2018-01-24 15:14

  本文关键词： CSTR 亚硝化颗粒污泥 氮容积负荷 EPS 氨氧化菌 功能菌活性　出处：《苏州科技大学》2017年硕士论文　论文类型：学位论文

【摘要】：污泥的颗粒化不仅有助于改善沉降性能,而且还可以富集生长较慢的硝化细菌,密实的生物结构对恶劣环境的抵抗能力也明显强于絮状污泥。“亚硝化技术”是指将水中氨氮氧化为亚硝态氮后,将亚硝态氮直接还原为氮气的过程。然而现行亚硝化工艺(如短程硝化-反硝化、短程硝化-厌氧氨氧化等)难以长期高效稳定运行,其中亚硝化的稳定性成为整个脱氮过程的限制性环节。目前好氧颗粒污泥大多在具有较大高径比的SBR反应器中培养及维持稳定,但在实际工程应用中间歇流受到诸多限制,故环保工程师的首选工艺模式为连续流。在连续流反应器中接种颗粒污泥并实现稳定的亚硝化性能,可为工程化提供可能。本论文系统地研究了CSTR中将异养型好氧颗粒污泥驯化培养为具有亚硝化功能的自养型颗粒污泥的变化过程;考察关键因素(氮容积负荷、C/N比)对亚硝化颗粒污泥的影响规律;并进一步探索了改善并实现亚硝化颗粒污泥工艺长期稳定运行的控制策略。本论文主要研究内容和研究结果如下:(1)通过在CSTR中接种由SBR反应器培养成熟的异养型好氧颗粒污泥,考察不同水力流态和进水基质下颗粒污泥的变化规律。结果表明,在前20d内异养型好氧颗粒污泥在连续流反应器中逐渐解体为接近絮状的污泥,沉降性能明显恶化;历时53天又重新生成小颗粒。在整个实验期间粒径小于0.3mm的颗粒迅速增加并一度成为主体,而粒径大于0.8mm的颗粒迅速减少。随着反应器运行,最终粒径0.3~0.8mm的颗粒成为主体。本阶段研究末期氨氮去除率和亚硝态氮积累率分别超过95%和80%并保持稳定。种泥中积累的大量胞外聚合物(EPS)在实现颗粒化的过程中起到了至关重要的作用,而低溶解氧(DO)(0.3~0.5mg·L~(-1))成为实现亚硝化的重要控制条件。(2)基于调控亚硝化颗粒污泥工艺的长期稳定运行。反应器整个运行共分为四个阶段(共181d)。研究结果表明,提升氮容积负荷(NLR)可以成为实现亚硝化工艺长期稳定运行的一种有效调控策略。随着反应器运行,颗粒形态越来越规则,且结构更加密实,可以有效应对短时间的高DO冲击,亚硝酸盐氧化菌(NOB)活性得到有效抑制。污泥去除负荷最高达到0.24kgN·(kg·d)~(-1),之后继续提升氮容积负荷会造成氨氮去除率下降,但亚硝态氮积累率始终高于80%。通过对功能菌活性的测定发现该颗粒具有较高的生物活性,其氨氮比去除速率[q(NH_4~+-N)]、亚硝态氮比积累速率[q(NO_2~--N)]、氨氧化菌比耗氧速率(SOUR-A)分别达到90±5mg·(g·h)~(-1)、80±5mg·(g·h)~(-1)、86±5mg·(g·h)~(-1)。另外,在以自养菌为主的颗粒中,EPS含量增加较缓慢,且主要是以蛋白质(PN)含量的增加为主,多糖(PS)含量则稳定在26~34mg·g~(-1)左右。(3)为探明易降解有机物短期冲击对全自养亚硝化颗粒污泥(PNG)中不同功能菌活性的影响,本研究采用多批次连续实验,系统考察了PNG在有机物胁迫与恢复阶段,氮素转化性能与溶解氧(DO)利用情况的演化规律。结果表明,基质C/N比越高,q(NO_2~--N)的降幅就越大。期间,异养菌(HeB)活性的增强,加快了PNG对DO的消耗速率,使得氧亲和力较差的亚硝酸盐氧化菌(NOB)活性得到了有效抑制。当重新采用无机碳源配水时,q(NO_2~--N)数值明显增大,同时HeB与NOB的活性均处于较低水平。因此,易降解有机物对全自养PNG系统的冲击具有一定可逆性,该过程有助于巩固氨氧化菌(AOB)的相对优势,提升亚硝化反应的稳定性。
[Abstract]:Granular sludge not only helps to improve the settling performance, but also can slow growth rate of nitrifying bacteria, biological resistance to harsh environment of the dense structure is significantly stronger than activated sludge. "The nitrosation technology" refers to the ammonia oxidation water for nitrite, the nitrite nitrogen direct reduction for the nitrogen process. However the nitrosation process (such as short cut nitrification and denitrification, SHARON-Anammox etc.) to long-term stable and efficient operation, the stability of nitrification denitrification process has become the restriction step. The aerobic granular sludge cultivation has mostly in the larger ratio of height to diameter of SBR reactor and maintain a stable, but intermittent flow restrictions in the middle of the actual engineering application, so the preferred environmental engineer process model for continuous flow. Inoculation of granular sludge and achieve stable nitrite in continuous flow reactors Performance can be engineered to provide the possibility. This paper systematically studied the aerobic granular sludge in CSTR heterotrophic cultivation and domestication process for autotrophic granular sludge with nitrification function; investigation of key factors (nitrogen loading, C/N ratio) influence on nitrification granular sludge; and to further explore the control strategy to improve and achieve long-term stable operation of nitrification granular sludge process. The main research contents and results are as follows: (1) in the CSTR through the SBR reactor inoculated by heterotrophic cultivation of mature aerobic granular sludge, the effects of different hydraulic flow and water changes of granular sludge substrate. The results showed that in the first 20d type of heterotrophic aerobic granular sludge in a continuous flow reactor is close to the gradual disintegration of flocculent sludge, settling performance deteriorated significantly; after 53 days of re generating small particles in the whole experiment. During the period of grain size less than 0.3mm particles increased rapidly and became the main body, and the particle size is greater than 0.8mm particles decreased rapidly. With the reactor operation, the final particle size of 0.3~0.8mm. This has become the main stage removal rate and nitrite nitrogen accumulation rate at the end of the study were more than 95% and 80% and remained stable. A lot of extracellular the accumulation of mud in the polymer (EPS) in the process of granulation plays a crucial role in, and low dissolved oxygen (DO) (0.3~0.5mg L~ (-1)) has become the important control condition for nitrification. (2) the long-term stable operation of the regulation of nitrification granular sludge process based on reaction. The whole operation is divided into four stages (181d). The results show that the increase of nitrogen volume load (NLR) can be an effective control strategy to achieve long-term stable operation of the nitrosation process. With the reactor operation, the particles form more and more rules, and 缁撴瀯鏇村姞瀵嗗疄,鍙�浠ユ湁鏁堝簲瀵圭煭鏃堕棿鐨勯珮DO鍐插嚮,浜氱�濋吀鐩愭哀鍖栬彛�

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