丝状细菌污泥膨胀的FISH探针研究进展

在活性污泥法处理污水的工艺中,丝状细菌的过度繁殖常引起大量的泡沫并引发污泥膨胀.该现象的发生导致二沉池的污泥不能有效地沉淀,并大量流出,影响了污水处理厂的正常操作.本文综述了引起污泥膨胀发生的7大类潜在丝状细菌及其相关生理生态学特性;列举了国内外现有的潜在丝状细菌的FISH探针及其相关的杂交条件.目前,在活性污泥丝状细菌的分类鉴定、胞外酶、细胞表面特性和相关生态生理学特性方面,荧光原位杂交(Fluorescence in situ hybridization,FISH)技术均起到重要的作用,而国内相关的研究很少.设计特异性的FISH探针,并以此进行定量荧光原位杂交,将是国内污泥膨胀问题未来研究的重点方向之一.表7参57     

pH对间歇进水序批式生物反应(SBR)工艺活性污泥沉降性能和微生物结构的影响

本文主要研究了不同pH值对SBR工艺污泥膨胀和微生物结构的影响,试验进水pH值为5.0—10.0.实验结果表明,在试验初期,污泥容积指数(SVI)值无明显变化.但随着时间的增长,在pH值为5.0和6.0时,开始出现污泥膨胀.在不同pH下提取总细菌的DNA组进行PCR扩增,分析总细菌的Shannon多样性指数,对微生物群落的部分优势总细菌进行克隆测序和系统发育树分析.结果表明,在不同pH条件下微生物结构以及数量有所区别,在酸性条件下以丝状菌为主,易发生污泥膨胀;而在中性和偏碱性条件下以菌胶团为主,污泥活性较为稳定.     

寒冷地区城市污水处理厂污泥膨胀及其控制

结合大庆乘风庄污水厂运行 5年来两次污泥膨胀的实例 ,对活性污泥系统发生污泥膨胀的主要原因进行了分析 ,提出在寒冷地区活性污泥系统中 ,除低氧、低负荷外 ,低温也是造成膨胀的原因之一。对此提出采用减小曝气池污泥浓度或单池连续运行以提高负荷和鼓风机进风口空气加热提高曝气池水温的方法 ,可使膨胀得到有效控制。     

A/O中试工艺中亚硝酸氮积累现象的消失与重现

应用A/O工艺处理低C/N比的生活污水,SRT维持在15d左右,水温控制在21-25℃,pH值在7.2-7.6之间,污泥浓度为2500-4500mg·l-1,通过控制溶解氧(DO)浓度实现了亚硝酸氮积累、消失和重现.维持较低的DO浓度(≤0.7mg·l-1)可使亚硝酸氮积累现象重现.在两次试验的比较中,亚硝酸氮积累破坏的愈彻底相应恢复的过程就愈漫长.在长期较低的DO浓度条件下,亚硝酸菌充分利用了有限的溶解氧,在与丝状菌竞争DO中占到优势,因此,污泥沉淀性能很好,没有产生严重污泥膨胀.同时分析了pH值、游离氨(FA)浓度、温度等对亚硝酸氮积累的影响,DO是影响亚硝酸氮积累的关键因素.     

投加甲烷鬃菌对厌氧颗粒污泥培养的影响

通过在中温条件下向EGSB(Expanded Granular Sludge Bed,膨胀颗粒污泥床)反应器中加入竹节状甲烷鬃菌6Ac,研究其对颗粒污泥形成的影响以及形成的颗粒污泥性质和反应器运行的情况.在(35±1)℃下,利用实验室相同规模的反应器,对照组(R1)接种厌氧絮状污泥,R2组接种厌氧絮状污泥的同时加入甲烷鬃菌,培养颗粒污泥.结果显示:当有机负荷(以COD计)逐步提高到11.1 kg m-3 d-1时,R2的COD去除率达到85.9%,高于R1的75.0%.运行到第46天(d 46)时两个反应器均可观测到颗粒污泥,R2中污泥粒径大于0.1 mm的颗粒污泥已经达到62.3%,d 28-46时,0.1-0.3mm颗粒的比例从10.0%增加到49.8%,对照组R1只从10%增加到33.3%,仍主要以絮状污泥为主.研究表明,颗粒污泥培养过程中投加甲烷鬃菌有利于促进颗粒污泥的形成、增殖与稳定,改善其沉降性能,提高有机物的去除效果,加快EGSB的启动.     

聚糖菌颗粒污泥的反硝化特性与微生物群落分布

为了解聚糖菌在污泥颗粒化中的脱氮能力及其微生物生态特性,采用反应器工艺、批式试验、显微技术和荧光原位杂交技术来评估其反硝化能力,揭示其微生物群落的微观结构,探索聚糖菌和聚磷菌在不同粒径污泥中的分布特征.结果表明,污泥对有机物的吸收率稳定在90%以上.颗粒污泥的沉降指数(SVI10)稳定在30-50 mL g-1,远低于接种污泥的108.2 mL g-1.聚醣菌颗粒污泥对硝酸盐氮和亚硝酸盐氮的反硝化去除率分别达到了65%和70%,氮气为主要气态产物.聚糖菌颗粒污泥被大量的四联球菌结构所充斥,丝状菌在其中起到了重要的构架和搭桥的作用.荧光原位杂交结果表明聚糖菌可生存于各尺寸颗粒化污泥内;而聚磷菌受到严重抑制只能较少地分布在颗粒污泥的外围空间.上述结果表明,在SBR反应器中采用厌氧搅拌—排水—好氧曝气的处理模式成功培育出具有聚糖特性的颗粒化微生物聚集体,培育成功的颗粒污泥对硝酸盐氮和亚硝酸盐氮均具有良好的反硝化特性.在整体颗粒污泥微生物群落中聚糖菌为优势种群.图8表1参19     

ABR反应器的启动及颗粒污泥特征的研究

在20-30℃条件下,对ABR反应器进行了169d 5个阶段的启动实验,进水COD容积负荷达到4.38kgCOD·m-3·d-1,出水COD,挥发性脂肪酸(VFA)和pH值达到要求;形成了大量的性能良好的颗粒污泥,其尺度介于2-3.8mm之间,沉降速度大于20m·h-1,MLVSS/MLSS值均大于65%;但各格室厌氧污泥的污泥指数(SVI)差异较大.显微分析表明,不同格室内呈现出种群配合良好的厌氧微生物分布,第一格室存在大量的优势发酵细菌,并有代谢乙酸的丝状甲烷细菌,然后颗粒污泥中的微生物逐渐向以产甲烷细菌优势菌群过渡,并存在许多浮游的原生和后生动物.另外,各格室中的颗粒污泥形状各异,表面凸凹不平,存在气孔,且颗粒污泥愈靠近核心,微生物数量愈少,细菌分泌物和无机质愈多.     

SBR/混凝协同工艺处理城市污水的效果

将无机混凝剂直接投加到SBR反应器中,组成SBR/混凝协同工艺对城市污水进行处理研究.考察了混凝剂的投加量、混凝剂的种类、投药时间等因素对污水处理效果的影响,探讨了新型复合混凝剂(PISC)对污泥膨胀的抑制作用.实验结果表明,与普通的序列间歇式活性污泥法(SBR)相比,当采用新型复合混凝剂与SBR组成的协同工艺处理城市污水时,在适宜的条件下,不仅污水中的CODCr、TP和sS的去除率可分别提高13.5%、47.6%和11.5%,水力停留时间缩短1/3左右,而且该协同工艺可明显抑制污泥膨胀,并改善高膨胀活性污泥的沉降浓缩性能.     

低温热氧化法强化剩余污泥微生物燃料电池的产电特性

城市污水处理厂污泥因有机物含量高而成为微生物燃料电池(MFC)应用研究的主要方向之一,而污泥中有机质的释放成为限制其发展的主要因素.本实验利用低温热解和过氧化氢氧化处理的耦合方法预处理城市污水处理厂污泥,分析了其作为燃料对MFC产电性能的影响.研究表明,利用预处理后的污泥上清液作为燃料,预处理温度、时间、pH值和过氧化氢投加量对MFC的产电性能影响大.当温度、时间、pH值和过氧化氢分别为100℃、90 min、11和500 g·kg TSS~(-1)的预处理条件下,MFC功率密度最大,分别为235、287、233.2、280 mW·m~(-3).采用热氧化法预处理污泥,可有利于污泥的破解,使能被产电菌利用的营养物质增多,提高了MFC产电特性,可为污泥资源化利用提供有益的参考.     

油田含油污泥的低温热解

在石油开采、集输和炼制过程中产生了大量的含油污泥,如果处置不当,将造成严重的环境污染.因此,研究含油污泥的无害化和资源化处理新技术是当务之急.含油污泥热解技术具有处置彻底、二次污染少等优点,是一种应用前景广阔的处理方法[1].本文制备了掺杂钯的钛氧化物介孔分子筛催化剂MCM41,利用真空管式热解炉对延长油田含油污泥进行低温热解,重点研究了热解条件和催化剂MCM41对油回收率和回收油中组分分布的影响.     

Control of sludge settleability and nitrogen removal under low dissolved oxygen condition

Low dissolved oxygen (DO) is an energy-saving condition in activated sludge process. To investigate the possible application of limited filamentous bulking (LFB) in sequencing batch reactor (SBR), two lab-scale SBRs were used to treat synthetic domestic wastewater and real municipal wastewater, respectively. The results showed that prolonging low DO aeration duration and setting pre-anoxic (anaerobic) phase were effective strategies to induce and inhibit filamentous sludge bulking, respectively. According to the sludge settleability, LFB could be maintained steadily by adjusting operation patterns. Filamentous bacteria content and sludge volume index (SVI) were likely correlated. SVI fluctuated dramatically within a few cycles when around 200 mL·g^-1, where altering operation pattern could change sludge settleability in spite of the unstable status of activated sludge system. Energy consumption by aeration reduced under low DO LFB condition, whereas the nitrification performance deteriorated. However, short-cut nitrification and simultaneous nitrification denitrification (SND) were prone to take place under such conditions. When the cycle time kept constant, the anoxic (anaerobic) to aerobic time ratio was determining factor to the SND efficiency. Similarity keeping aerobic time as constant, the variation trends of SND efficiency and specific SND rate were uniform. SBR is a promising reactor to apply the LFB process in practice.     

Cultivation of aerobic granular sludge in a conventional,continuous flow,completely mixed activated sludge system

Aerobic granules were formed in a conventional, continuous flow, completely mixed activated sludge system (CMAS). The reactor was inoculated with seed sludge containing few filaments and fed with synthetic municipal wastewater. The settling time of the sludge and the average dissolved oxygen (DO) of the reactor were 2 h and 4.2 mg·L^-1, respectively. The reactor was agitated by a stirrer, with a speed of 250 r·min^-1, to ensure good mixing．The granular sludge had good settleability, and the sludge volume index (SVI) was between 50 and 90 mL·g^-1. The laser particle analyzer showed the diameter of the granules to be between 0.18 and 1.25 mm. A scanning electron microscope (SEM) investigation revealed the predominance of sphere-like and rod-like bacteria, and only few filaments grew in the granules. The microbial community structure of the granules was also analyzed by polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). Sequencing analysis indicated the dominant species were α, β, and γ-Proteobacteria, Bacteroidetes, and Firmicutes. The data from the study suggested that aerobic granules could form, if provided with sufficient number of filaments and high shear force. It was also observed that a high height-to-diameter ratio of the reactor and short settling time were not essential for the formation of aerobic granular sludge.     

A hybrid membrane process for simultaneous thickening and digestion of waste activated sludge

A hybrid membrane process for simultaneous sludge thickening and digestion (MSTD) was studied. During one cycle (15 d) of operation under a hydraulic retention time of 1 d, the concentration of mixed liquor suspended solids (MLSS) continuously increased from about 4 g·L⁻¹ to 34 g·L⁻¹, and the mixed liquor volatile suspended solids (MLVSS) increased from about 3 g·L⁻¹ to over 22 g·L⁻¹. About 42% of the MLVSS and 39% of the MLSS reduction were achieved. The thickening and digestion effects in the MSTD were further analyzed based on a mass balance analysis. Test results showed that biopolymers and cations of biomass were gradually released to the bulk solution during the process. It was also found that the capillary suction time, colloidal chemical oxygen demand, soluble microbial products, viscosity, and MLSS had significant positive correlations with the membrane fouling rate, whereas extracellular polymeric substances, polysaccharides, and proteins extracted from biomass had negative impacts on membrane fouling.     

污水处理中的污泥减量新技术

污水好氧处理会产生大量污泥，剩余污泥的处理成本高昂，减少污泥产量势在必行。文章介绍了代谢解偶联、增加维持能量消耗、隐性生长、微型动物捕食、高溶解氧工艺和膜生物反应器等污泥减量技术，比较了各种技术的优缺点，指出了不同技术结合将成为污泥减量技术的发展方向。     

臭氧对活性污泥性状的影响

分别在臭氧浓度为31.50,31.96,32.23,33.89,36.65,39.33和40.25mg·l-1下,考察污泥混合液MLSS,MLVSS和pH值及上清液SCOD,TN,NH3-N和,TP等随臭氧作用时间的变化.结果表明:臭氧对污泥混合液中的溶解性同体(DS)具有氧化作用,能有效破解微生物絮体、细胞壁和细胞膜等,使微生物体内有机质溶出,溶出物能被微生物作为底物重新利用,本实验中,MLSS和MLVSS降低最大量分别为1250 mg·l-1和465 Mg·l-1,SCOD增加最大量为250.3 mg·l-1.另外,根据混合液各性状的变化规律分析了臭氧氧化污泥的机理.     

活性污泥动力学模型的建立及在完全混合式污泥系统中的应用

首先建立了微生物衰减系数和污泥浓度、底物浓度的函数关系式,带入Lawrence-McCarty第一方程式得到了Logistic方程形式的微生物生长方程式.在分析污泥泥龄和污泥停留时间关系基础上,引入Monod方程建立了活性污泥动力学模型,推导证明了Lawrence-McCarty方程式是模型静态条件下的表达形式.用建立的活性污泥动力学模型对完全混合式污泥系统进行了模拟,并分析了水力停留时间Hydraulic retention time(HRT)和污泥停留时间Sludge retention time(SRT)对完全混合式污泥系统的影响,表明模型能很好地对活性污泥系统的动态过程进行模拟.根据模型编程画出了污泥系统相关变量关于HRT和SRT变化的三维曲面图,通过编程将复杂模型看作一定输入输出的函数,使得模型更易于应用和推广.     

臭氧污泥减量过程中混合液各参数的变化

实验用污泥的初始浓度(MLSS)分别限定为4g/L、7g/L和11g/L,用以探讨不同浓度下臭氧氧化过程中COD、N和P浓度的变化。结果表明:臭氧氧化过程中,MLSS和MLVSS基本呈线性下降;臭氧对污泥细胞的溶解可以引起混合液中COD、N和P浓度的升高,升高速率受污泥浓度和臭氧浓度影响较大;TKN和硝态氮是N的主要存在形式,TKN和TN随时间均呈先增加后趋缓的变化规律;臭氧对氨氮和亚硝酸盐氮有较强的氧化能力,二者浓度均呈先增大后减小的规律;而硝酸盐氮呈一直增加趋势;臭氧对COD的氧化也很明显,表现为COD的增加速率随氧化时间的增加而不断降低;总磷的浓度基本呈线性增加,单位质量污泥的总磷释放量差异不大;臭氧对MLSS的彻底减量会引起臭氧溶胞利用率的降低,因此应该合理控制臭氧化反应的时间。     

Assessing water quality in the Ceyhan River basin (Turkey) with the use of aquatic macrophytes

As a major biotic component of many lotic ecosystems, macrophytes consist a major component of running waters are often used as indicators within the European Water Framework Directive (WFD) to establish ecological quality. In this study, we investigated macrophyte community structure (e.g. composition, abundance and diversity) in Ceyhan River Basin located in the Southeastern Anatolian Region in Turkey. Data was collected during 2014–2015 from river sites located throughout the basin to evaluate the relationship between aquatic vegetation and river physico-chemical factors. The ecological status of the river basin was also calculated based on Macrophyte Biological Index for River (IBMR). In total, 33 macrophyta taxa were observed. According to their biological classification (life form), filamentous algae (FA), free floating (FF), floating leaved (FL) and submersed (S) macrophytes reached their maximum abundance value in summer, while emergent (E) macrophytes were at their maximum abundance in both summer and autumn. The ecological status of the Ceyhan River basin ranged from moderate to bad. The values found are reasonably comparable to IBMR scores recorded in rivers of other Mediterranean countries. IBMR index may be suitable to some extent to establish a basis for ecological quality assessment in Turkish River systems.