桐乡市城市污水处理厂对丝状菌污泥膨胀的控制实践

介绍了桐乡市城市污水处理厂丝状菌污泥膨胀的处理对策,对发生污泥膨胀时的水质特点、工况条件进行分析,认为此次丝状菌污泥膨胀主要是由于低污泥负荷率、低溶解氧引起的。通过调整泥龄、污泥负荷、DO等运行参数,投加NaClO溶液杀灭丝状菌等措施成功控制了此次污泥膨胀,可供同行参考。     

丝状菌污泥膨胀理论分析

对丝状菌污泥膨胀现象进行了综合分析,并在广义Monod方程的基础上基本统一了污泥膨胀理论和建立了相关的数学模型。该模型可以很好地解释由基质限制、DO限制、营养物缺乏、pH和H2S等因素引起的丝状菌污泥膨胀。利用广义Monod方程采用双基质限制（碳源和溶解氧）模型和系统动力学方程进行了计算机模拟研究,对有机负荷、DO、水质和水量变化等因素对细菌和丝状菌的竞争影响进行了深入的探讨,并在此基础上针对不同的污泥膨胀类型提出了相应的控制策略。     

SBR工艺中污泥负荷对丝状菌污泥膨胀的影响

在严格控制ＳＢＲ工艺试验运行条件下,就污泥负荷对丝状菌污泥膨胀的影响规律进行了研究。结果表明,高污泥负荷不仅不是导致污泥膨胀的因素,而且对污泥膨胀有抑制作用;在污泥负荷降低到一定程度（“临界负荷”）后,ＳＶＩ迅速升高,加速污泥膨胀的发生。还发现,进水底物浓度与“临界负荷”及低于“临界负荷”后污泥膨胀的最大程度ＳＶＩｍａｘ之间呈负相关关系,且都可用微生物的选择性理论来解释。     

温度波动对SBR污泥沉降性的影响及其变化规律

在以A<'2>/0方式运行的SBR中,采用人工废水研究了温度降低再升高过程中污泥沉降性能的变化.结果表明,一旦反应器水温由25℃以上降低到15℃以下,污泥就会发生膨胀,当再升温至25℃以上时,污泥膨胀消失,污泥沉降性能恢复到良好状态.在降温-温度恢复的这一过程中,污泥沉降性能恢复所花费的时间比发生膨胀所需的时间长.降温对可导致污泥膨胀的微生物的促进作用要比升温对该微生物的抑制作用、对菌胶团的促进作用显著.在温度波动过程中,当系统发生的是单一高粘性膨胀时,污泥沉降性能恢复时间是污泥膨胀发生时间的2倍;当系统发生的是丝状膨胀和高粘性膨胀并存的污泥膨胀时,污泥沉降性能恢复时间是污泥发生时间的9倍.在降温波动过程中,污泥沉降性能恢复时间与系统内存在的丝状菌种类有关,当污泥膨胀发生后系统中存在能适应低温环境并生长的丝状菌时,污泥沉降性能恢复时间就较长,但这有利于恢复后形成密实的污泥絮体.     

炼油化工污水处理中活性污泥膨胀原因分析

针对工业废水采用普通活性污泥法处理易出现的丝状菌型污泥膨胀,分析和总结出五种主要膨胀类型：低负荷型、低溶解氧型、营养缺乏型、高硫化物型、pH值不平衡型。对污泥负荷、溶解氧、污水种类、营养成分及pH值和温度的变化等因素对污泥膨胀中菌胶团和丝状菌生长的相互影响进行阐述,给出污泥膨胀理论,并对不同类型的污泥膨胀提出相应的控制方法。     

好氧颗粒污泥发生丝状菌污泥膨胀的控制措施

在SBR反应器内接种好氧颗粒污泥,经驯化后对人工模拟废水的处理效果良好。考察了培养过程中污泥形态的变化以及发生丝状菌污泥膨胀时反应器对污染物的去除效果,并探讨了丝状菌在污泥颗粒化过程中的作用以及控制丝状菌污泥膨胀的方法。结果表明,丝状菌污泥膨胀对COD的去除率有影响,但对去除NH3-N、TP的效果影响不大。通过增加反应器内的水力剪切力对控制丝状菌污泥膨胀有一定的效果,而减小C/N值,均衡进水中的营养可从根本上解决污泥膨胀问题。成熟的好氧颗粒污泥的MLSS约为3 000 mg/L,沉降性能较好,SVI为77 mL/g;对COD、NH3-N、TP均具有较高的去除率,分别达到94.52%9、5%9、0%左右。     

低温条件下SBR活性污泥膨胀及控制

通过对实验室SBR中污泥膨胀类型的判别,发现低温条件下污泥膨胀是由非丝状菌过度繁殖引起的。通过试验发现一方面可以通过提高水中溶解氧、降低污泥负荷以及增加排泥次数能有效控制非丝状菌污泥膨胀,另一方面通过投加聚合氯化铝、三氯化铁、聚合硫酸铁等混凝剂可以改善活性污泥沉降性能,但抑制污泥膨胀周期较短,另外投加高锰酸钾氧化剂和聚丙烯酰胺对非丝状菌的抑制效果不明显。     

非丝状菌污泥膨胀对无排泥MBR的影响

在无排泥条件下,通过对MBR系统中发生的非丝状菌污泥膨胀现象的研究发现:污泥膨胀导致污泥沉降性变差,系统污泥量上升,对TN的去除率较低且不稳定,但对COD和氨氮的去除效果影响不大,去除率分别能达到80%和90%以上;在初期对TP的去除率较高,随着污泥停留时间的延长,对TP的去除率逐渐下降。通过减少曝气量、降低进水COD和TN浓度、增加进水TP浓度,能有效解决MBR中发生的非丝状菌污泥膨胀现象,同时能降低污泥产率。     

A/O除磷工艺丝状菌污泥膨胀的研究

丝状菌污泥膨胀是影响活性污泥法高效、稳定运行的重要因素。采用A/O生物除磷工艺中试装置处理实际生活污水,分析了污泥膨胀发生的原因及恢复系统性能的方法。结果显示,长期曝气不均匀是导致丝状菌污泥膨胀的重要原因,通过调控系统运行参数可以有效控制由低DO值或者高负荷引起的丝状菌污泥膨胀。当发生污泥膨胀后,首先降低负荷至0.45 kgCOD/(kgMLSS.d),调节回流比为83%,同时控制好氧池各段的DO分别为1.5、1.0、1.0 mg/L以淘汰丝状菌,在SVI值降至200 mL/g以下后继续降低回流比至53%,同时降低曝气量以形成1.0、0.5、0.5 mg/L的DO浓度梯度。采取上述调控措施后,SVI值由569.8 mL/g降至150 mL/g以下,污泥性状得以恢复;同时出水COD和TP分别在50、0.5 mg/L以下,去除率分别约为85%、95%。     

活性污泥法中引起丝状菌污泥膨胀的因素

活性污泥法是采用最普遍的污水处理工艺,而丝状菌污泥膨胀则是该工艺污水运行中易发生、危害大的问题.介绍了近30 年来国际上关于丝状菌污泥膨胀的最新研究成果,分析了影响丝状菌污泥膨胀的主要因素.     

A technique for normalizing the operation of biological wastewater treatment plants during the bulking of activated sludge

A technique for normalizing the operation of biological wastewater treatment plants during the bulking of activated sludge by feeding oxychloride coagulants at the stage of gravity separation of sludge-water mixture has been investigated. The optimal dosage of the reagent and its effect on the process-dependent parameters of activated sludge and the purification quality were established. In addition the dynamics of rehabilitation of the bulking activated sludge was also investigated.     

印染废水处理中的污泥膨胀与控制

分析了水解酸化／UASB／SBR工艺处理印染废水过程中发生污泥膨胀的可能原因，并通过试验考察了投加氮和磷与预曝气对污泥膨胀的控制效果。结果发现只投加氮、磷未能控制污泥膨胀，而预曝气则可使污泥膨胀得到很好的控制。结合水质分析的结果，得知污泥膨胀的原因是硫化物浓度过高。     

Stable Foams and Sludge Bulking: The Largest Remaining Problems (Abridged)

The separation of activated sludge in secondary settling tanks is the crucial step in biological wastewater treatment from the point of view of both final effluent quality and operation of the aeration plant. The sludge-separation problems of bulking and foaming are connected with an excessive growth of filamentous micro-organisms in the biocenosis of activated sludge.
This paper (a) describes the methods which are used for the quantification of activated-sludge separation problems, and (b) summarizes the design recommendations for bulking and foaming control.     

电解/水解酸化/活性污泥法处理医药废水研究

采用电解/水解酸化/好氧活性污泥工艺处理高浓度、难降解的医药生产废水,着重考察了HRT、温度、pH、溶解氧及污泥负荷对好氧段处理效果的影响.结果表明,电解/水解酸化提高了废水的可生化性,在HRT为18 h、温度为24℃、pH值为6.5～7.0、溶解氧为2.5 mg/L以及污泥负荷为0.42～0.50 kgCOD/(kgMLSS·d)的条件下,好氧段对COD的去除效果较好,去除率基本稳定在90%左右,出水水质满足<污水综合排放标准>(GB 8978-1996)的二级标准.     

高浓度消毒剂对活性污泥系统中微生物的影响

针对污水厂活性污泥易于发生丝状菌污泥膨胀问题,以西安市第二污水处理厂活性污泥为研究对象,在次氯酸钠投加量为15 mg/L的条件下,探索高浓度消毒剂对活性污泥中微生物的杀灭效果以及对胞外聚合物(EPS)含量和不同类型微生物活性的影响。结果表明,高浓度次氯酸钠能有效杀灭丝状菌,从而控制污泥的丝状膨胀现象,但在杀灭丝状菌的同时也会影响菌胶团絮体内的部分微生物,且对不同微生物的杀灭效果不同,亚硝酸盐氧化菌(NOB)是最易被杀灭的类型。当次氯酸钠投加量为15 mg/L时,反应3 h后污泥胞外聚合物总含量降低了15. 48%,硝化活性丧失殆尽且再未恢复,反硝化活性下降明显;恢复7 d后,絮体内部微生物可以得到有效恢复,而丝状菌大多依然处于死亡状态,EPS总含量继续下降。总之,高浓度消毒剂作用于活性污泥后,可以达到控制丝状菌的目的,但是污泥的硝化和反硝化活性也受到了影响。     

膜生物反应器发生污泥膨胀后的控制措施研究

以膜生物反应器处理学校洗浴污水,考察了污泥发生膨胀时反应器对污染物的去除效果,并探讨了控制污泥膨胀的方法。结果表明,污泥膨胀对膜生物反应器去除COD和BOD5的效果影响不大,但会使系统对氨氮的去除率有所下降。采用化学絮凝法控制污泥膨胀,静态试验结果表明三氯化铁和聚丙烯酰胺的絮凝效果较为理想,但现场投加时发现,反应器内较强的水力搅拌作用使得聚丙烯酰胺的絮凝效果变差,而三氯化铁可作为控制污泥膨胀的应急措施,采用营养平衡法可从根本上解决污泥膨胀问题。     

Challenges in determining causation in structure-function studies using molecular biological techniques

The use of molecular biological techniques for determining the levels and types of different microbial populations in bioreactors has led to the emergence of the microbial community ‘structure-function’ paradigm that is often used in research. Typically, lab- or full-scale systems are monitored for the relevant parameters, and these parameters are related to the changes in microbial populations. Research in activated sludge phenomena, such as filamentous bulking, filamentous foaming, nitrogen removal, and phosphorus removal, are replete with many examples of this ‘structure-function’ paradigm, most commonly those that involve 16S rRNA gene-based analysis of the microbial populations. In many cases, such studies assume a causal microbial population (e.g., a species that causes bulking or foaming), or conclude in identifying a causal population. However, assigning cause to specific organisms and populations is problematic in a complex environment such as wastewater bioreactors. The Koch-Henle postulates, the gold standard in evaluating causation of disease, have limitations when applied to systems with mixed microbial communities with complex interactions, particularly if pure cultures are not available. Molecular techniques that allow specific identification and quantification of organisms have been used by researchers to overcome the limitations of culture-based techniques, and at the same time, raised new questions on the applicability of causation postulates in environmental systems. In this paper, various causation criteria improving on the Koch-Henle postulates are presented. Complicating issues in assigning cause in wastewater bioreactors are identified. Approaches for determining cause-effect relationships are illustrated using 16S rDNA-based investigations of filaments that cause bulking and foaming in activated sludge. The hope is that a causation framework that accounts for the assumptions in molecular studies, as applied to wastewater treatment research, will lead to improved experimental design and analysis of data.     

Ecological study of activated sludge settling property in the completely mixed system

The bulking problem associated with both nitrogen-rich and nitrogen-deficient activated sludges was thoroughly investigated under a DO sufficient condition in the completely-mixed continuous flow system. The reactor temperature was controlled at 27 ± 1°C and the pH was maintained at nearly equal to 7.0. The activated sludge cultures were acclimated under various organic loadings and their settling characteristics were determined by sludge volume index and zone settling velocity. The contents of sludge protein and carbohydrate along with the cell surface charge were examined for understanding the correlation between sludge composition and sludge settleability. Also, the major types of long-length filaments existed in the bulky activated sludge were identified. Moreover, the effect of sludge settleability on effluent quality was determined.