好氧颗粒污泥的特点及其研究进展

综述了好氧颗粒污泥的基本特征和微生物相、好氧颗粒污泥形成的主要影响因素及其颗粒化反应器等。好氧颗粒污泥是近几年发现的在好氧条件下自发形成的细胞自身固定化过程 ,是生物膜特殊的生长形式。颗粒污泥具有良好的沉降性能、较高的生物量和在高容积负荷条件下降解高浓度有机废水的良好生物活性。污泥颗粒化过程是一个多阶段的过程 ,取决于废水组成及其操作条件的选择。在气提式内循环间歇反应器 (internalcirculatesequencingbatchairliftreac tor ,ICSBAR )中易于培养出性能良好的好氧颗粒污泥。     

混凝强化形成好氧颗粒污泥

为了缩短好氧颗粒污泥形成的时间,通过在颗粒污泥形成初期投加混凝剂的方式,研究强化造粒条件下颗粒污泥的形成过程及其特性。结果发现,投加混凝剂后,反应器在第8天出现了颗粒污泥,并在第25天时实现完全颗粒化,比未加混凝剂反应器颗粒形成的时间缩短了2 d,完全颗粒化时间缩短了10 d。强化造粒条件下形成的颗粒污泥,颗粒强度、比重分别为99.03%和1.1892,分别比对照高出3.28%和0.1539。可以看出,在混凝强化造粒条件下培养出的颗粒污泥,与常规方法相比具有颗粒化进程快,颗粒强度大,比重大等优点。     

好氧颗粒污泥处理高浓度氨氮废水的研究

在不同接种源污泥颗粒化过程中污泥理化性状对比研究的基础上,采用成熟好氧颗粒污泥处理高浓度氨氮废水,对其脱氮行为以及不同C/N条件下好氧颗粒污泥微生物的比耗氧速率、好氧颗粒污泥对氨氮的比降解速率随时间的变化等进行了研究.实验结果表明,在进水氨氮质量浓度较高(480 mg/L)、温度30℃左右的条件下,稳定运行15 d,氨氮的去除率维持在85%左右;进水氨氮的浓度越高,随着微生物对环境的逐渐适应,硝化菌的活性也逐步增加;随着进水氨氮浓度的提高,好氧颗粒污泥对氨氮的比降解速率也逐渐上升.     

低强度超声波强化剩余活性污泥好氧消化的研究

污泥是城市污水处理厂的副产物,若处理不当,将会带来一系列严重的环境问题.实验采用低强度超声波对剩余活性污泥(WAS)的好氧消化过程进行强化,选取超声强度、超声时间、超声间隔3个因素设计正交实验.结果表明,经超声辐照的WAS,其好氧消化时间最短仅约为13 d,比未经超声辐照的缩短了18.00 d.对实验结果的极差分析和方差分析表明,低强度超声波强化WAS好氧消化的最佳参数为:超声强度1.0 W/cm2、超声时间10 min、超声间隔8 h.实验还研究了WAS达标前后溶解性化学需氧量(SCOD)和总化学需氧量(TCOD)的变化情况,发现在相对较短的处理时间内,经低强度超声波强化处理的WAS的TCOD降解率仍然能与对照相近甚至高于对照,主要原因是低强度超声波强化了微生物的新陈代谢,促进了其对有机物的吸收分解.     

颗粒化序列间歇式活性污泥反应器工艺处理化粪池污水

在序列间歇式活性污泥反应器(SBR)中成功培养出适应化粪池污水水质的好氧颗粒污泥.并将其应用于化粪池污水的处理.在好氧颗粒污泥培养的第15天左右,SBR中开始出现细小的颗粒,然后微生物在其上繁殖生长使颗粒逐渐增大而成熟;在第24天时,SBR中絮状活性污泥已基本实现了颗粒化.培养出的好氧颗粒污泥对化粪池污水有稳定的处理效果,在进水完全为化粪池污水时,COD、NH_4~+-N、TN的平均去除率分别为77%、61%、47%.但是,由于化粪池污水COD较低,因此无法维持较高的生物量,在后期的稳定运行过程中MLSS始终维持在2 500 mg/L左右.好氧颗粒污泥的同步硝化反硝化作用是其稳定脱氮的保证.     

曝气量和曝气时长对好氧颗粒污泥活性恢复的影响

采用啤酒废水,在SBR中对在4℃的冰箱中储存8周的好氧颗粒污泥进行活性恢复。设置曝气时长分别为150 min和270 min,曝气量分别为0.1 m3/h和0.2 m3/h,考察了曝气时长和曝气量对好氧颗粒污泥活性恢复的影响。实验结果表明,好氧颗粒污泥在4℃冰箱中储存8周后,其颜色、粒径无明显变化;设置较长曝气时间(270 min)、较大曝气量(0.2 m3/h)时,颗粒污泥平均沉降速率、MLSS和SVI恢复最快,且对COD处理效果也恢复较快。而短曝气时间(150 min)、小曝气量(0.1 m3/h)有利于好氧颗粒污泥对氨氮去除效果的恢复。     

实际污水与模拟污水活性污泥系统的特性差异

实验中经常采用人工配置的模拟生活污水,为了研究其与实际生活污水活性污泥系统的特性差异,采用2个序批式间歇反应器(SBR)进行平行实验(厌氧、好氧方式运行),系统地考察了在进水主要组分和运行参数相同的情况下,不同原水对活性污泥系统脱氮、除磷、比好氧速率、污泥絮体形态和出水水质等方面的影响。结果表明,模拟污水系统的硝化活性强于实际污水系统,两者的平均硝化速率分别为7.43 mg NH4+-N/(L.h)和5.55 mg NH4+-N/(L.h)。在前置厌氧段,模拟污水系统的释磷量比实际污水系统高出36.45%。两者在后续好氧阶段都能够充分吸磷。模拟污水系统的平均比好氧速率(SOUR)高达64.54 mg O2/(g MLSS.h),而实际污水系统的则只有32.81 mg O2/(g MLSS.h)。模拟污水系统的污泥絮体疏松,粒径小,形状不规则,沉降性差,沉后出水平均悬浮物浓度(SS)为20 mg/L;而实际污水系统的污泥絮体则密实、粒径大,沉降性好,沉后水十分清澈,SS几乎检测不出。     

好氧颗粒污泥的性质及其在脱氮除磷中的应用

阐述了好氧颗粒污泥的污泥特性、培养条件和影响因素 ,比较了三种SBR反应器中颗粒污泥特性的差异 ,介绍了好氧颗粒污泥的形成机理及其在脱氮除磷过程中的应用情况     

颗粒污泥与絮状污泥处理垃圾渗滤液的耐盐性能比较

通过批次实验系统研究了好氧颗粒污泥和絮状污泥处理垃圾渗滤液时的耐盐性能。实验结果表明,进水含盐量小于10 000 mg/L时,实验所用好氧颗粒污泥和絮状污泥的有机物去除能力、沉降性能、污泥活性基本上不受进水含盐量变化的影响。当进水含盐量大于10 000 mg/L时,随着进水含盐量的增大,絮状污泥的污泥沉降指数(SVI)快速减小,污泥活性及去除有机物的能力下降;相比而言,好氧颗粒污泥沉降性能更为稳定,SVI基本维持在30 mL/g左右,污泥活性及去除有机物的能力缓慢下降。当进水含盐量重新降低时,好氧颗粒污泥沉降性能变化不大,污泥活性及去除有机物的能力恢复迅速;而絮状污泥沉降性能变差,污泥活性及去除有机物的能力仍受较大抑制。     

Correlation analysis of major control factors for the formation and stabilization of aerobic granule

In recent years, aerobic granular sludge technology has demonstrated significant advantages in areas such as the sludge–water separation, residual sludge minimization, simultaneous biological nitrogen and phosphorus removal, and toxic organic compounds degradation in biological wastewater treatment. However, the critical control factors and their relation during sludge granulation have not been revealed indeed, and the stability of aerobic granular sludge is still not good. The Gray’s correlation analysis was used to investigate the relationship of aerobic granular characteristics and control factors in the study. Results showed that the organic loading rate, hydraulic shear stress, and sludge settling time were the major factors affecting the aerobic sludge granulation, and the associated regulating strategy was important for the stabilization of granular sludge system. Based on above results, the mechanism of aerobic sludge granulation was proposed, and it was expected to favor the application of aerobic granular sludge technology.     

好氧颗粒污泥的形成过程、形成机理及相关研究

利用SBR和优势混合菌对造纸废水进行处理,在此过程中驯化出好氧颗粒污泥,对好氧颗粒污泥的形成过程、形成机制等进行研究发现,好氧颗粒污泥的形成经历了细菌增殖、絮状体形成、絮状体聚合、凝絮体形成和好氧颗粒污泥形成五个阶段;其形成至少有菌丝缠绕、小块污泥互相联合、吸附和连接四种机制。优势混合菌的加入,是好氧颗粒污泥之所以能够形成的关键因素。     

Simultaneous nitrification and denitrification in an aerobic reactor with granular sludge originating from an upflow anaerobic sludge bed reactor.

Anaerobic granular sludge, obtained from an upflow anaerobic sludge bed reactor at a brewery waste treatment station, was cultured for 3 months under aeration conditions until the diameter of sludge was in the range 1.8 to 2.6 mm. The aerobic granular sludge gathered acquired the ability of catalyzing simultaneous nitrification and denitrification (SND) and was applied in the study of the process of nitrogen removal in a bioreactor. The ratio between chemical oxygen demand (COD) and ammonium-nitrogen (NH4(+)-N) concentration in the influent was found to be an important factor influencing the process of SND. The final percentage removal of NH4(+)-N reached 100% under the optimal condition of 500 mg/L COD and 0.39 NH4(+)-N/COD. Intermediate products, such as nitrite-nitrogen and nitrate-nitrogen, were also analyzed to clarify the SND process with the aerobic granular sludge.     

SBR工艺活性污泥比耗氧速率与控制参数的关系

活性污泥的比耗氧速率(SOUR)是表征污泥生物活性的重要参数之一,从微生物呼吸速率角度反映了活性污泥生理状态和基质代谢状况.通过监测SBR工艺活性污泥的SOUR,考察了SBR工艺中活性污泥SOUR的变化规律,研究了活性污泥的SOUR与各项控制参数之间的相关关系.试验结果表明,活性污泥的SOUR可以有效地表征SBR工艺的生化反应进程,并与DO、氧化还原电位(ORP)和pH之间存在良好的相关关系.     

酸度对好氧颗粒污泥生物吸附含铅废水影响的研究

为了有效地控制铅污染，利用序批式反应器（sequencing batch reactor,SBR）培养的以醋酸钠为碳源的好氧颗粒污泥作为吸附剂，进行生物吸附含铅废水的效能和机理的研究。通过考察酸度、接触时间和Pb²⁺初始浓度等因素的影响，验证好氧颗粒污泥吸附模型，并利用不同的脱附剂，进一步解析其生物吸附的Pb²⁺。实验结果表明, 酸度是影响好氧颗粒污泥生物吸附Pb²⁺的关键因素，当初始pH为5时，好氧颗粒污泥对含铅废水生物吸附效果最好。对低浓度（0～20 mg/L）含铅废水， 10 min后可快速达到吸附平衡。好氧颗粒污泥对Pb²⁺的实测饱和吸附量为101.97±9.00 mg/g，符合朗缪尔（Langmuir）模型。好氧颗粒污泥生物吸附Pb²⁺的过程，伴随着pH值的升高和K⁺、 Ca²⁺、 Mg²⁺的释放，此现象揭示离子交换作用是好氧颗粒污泥生物吸附Pb²⁺的机理之一。此外，脱附剂HNO₃、EDTA和CaCl₂能实现Pb²⁺的回收和好氧颗粒污泥的重复利用。     

A rapid, direct measurement of bacterial growth rate in anaerobic wastewater treatment.

Reliable design and operation of biological wastewater treatment systems demand robust models of biological degradation processes. However, methods to directly measure key bacterial growth kinetics have not been readily available. Those methods that are available rely on the classic measurement of aerobic respiration using oxygen uptake take rates. This paper shows how the thymidine assay can be used as a rapid and direct measurement of bacterial specific growth rates (mu) in situ for an anaerobic treatment process, independent of aerobic respiration. A filtration-based assay is applied and evaluated a dispersed-phase high-rate anaerobic treatment process, with results obtained in less than an hour. The chemical oxygen demand (COD) biomass in the reactor was 0.52 kg COD m(-3) and the specific growth rate of these anaerobic bacteria was 0.8 +/- 0.2 d(-1). It took the bacterial populations 21.6 hours to double. This is an important advancement from existing methods that use aerobic respiration as a pseudo measurement of bacterial specific growth rates. The method allows rapid and direct measures of microbial growth rates for anaerobic treatment processes.     

厌氧氨氧化菌接种污泥的选择培养过程研究

厌氧氨氧化菌的2种不同接种污泥培养实验表明,厌氧消化污泥和好氧硝化污泥均可成功启动厌氧氨氧化过程.接种厌氧消化污泥比好氧硝化污泥培养的厌氧氨氧化菌启动快,但后者去除效果较好.接种好氧硝化污泥的反应器的厌氧氨氧化速率随着氨氮基质进水浓度的增加呈线性增加.进水氨氮浓度为280 mg/L时的氨氮平均去除率达91%;而接种厌氧消化污泥的相应氨氮平均去除率仅为52%.厌氧氨氧化过程以接种好氧硝化污泥来启动为宜.     

螺旋升流式反应器脱氮除磷系统的运行效果与污泥性能分析

对螺旋升流式反应器脱氮除磷及去除COD的运行效果进行了研究 ,该系统连续稳定运行 6个月的结果表明 ,能保证出水平均质量浓度TN小于 1 0mg/L ,TP小于 0 5 0mg/L ,COD小于 31mg/L ,对TN、TP和COD的去除率分别达 86 %、96 %和 94 %以上。并且对SUFR系统的污泥性能进行了分析 :(1 )螺旋升流特征使本反应系统中的污泥易于颗粒化 ;(2 )SUFR系统中的微生物种群具有多样性 ;(3)污泥在好氧反应器中表现出了同步硝化反硝化功能 ;(4 )污泥在缺氧反应器表现出了反硝化吸磷现象     

Denitrification of synthetic concentrated nitrate wastes by aerobic granular sludge under anoxic conditions

The aim of the present work was to determine the denitrification potential of aerobic granular sludge for concentrated nitrate wastes. We cultivated mixed microbial granules in a sequencing batch reactor operated at a superficial air velocity of 0.8 cm s⁻¹. The denitrification experiments were performed under anoxic conditions using serum bottles containing synthetic media with 225-2250 mg L⁻¹ NO₃-N. Time required for complete denitrification varied with the initial nitrate concentration and acetate to nitrate-N mass ratio. Complete denitrification of 2250 mg L⁻¹ NO₃-N under anoxic conditions was accomplished in 120 h. Nitrite accumulation was not significant (<5 mg N L⁻¹) at initial NO₃-N concentrations below 677 mg L⁻¹. However, denitrification of higher concentrations of nitrate (?900 mg N L⁻¹) resulted in buildup of nitrite. Nevertheless, nitrite buildups observed in present study were relatively lower compared to that reported in previous studies using flocculent activated sludge. The experimental results suggest that acetate-fed aerobic granular sludge can be quickly adapted to treat high strength nitrate waste and can thus be used as seed biomass for developing high-rate bioreactors for efficient treatment of concentrated nitrate-bearing wastes.     

Persistence of perfluoroalkylated substances in closed bottle tests with municipal sewage sludge

BACKGROUND, AIM, AND SCOPE: Perfluoroalkylated substances (PFAS) are chemicals with completely fluorinated alkyl chains. The specific properties of the F-C bond give PFAS a high stability and make them very useful in a wide range of applications. PFAS also pose a potential risk to the environment and humans because they have been recently characterized as persistent, bioaccumulative, and toxic. The objective of this work is to study the bacterial degradation of PFAS under aerobic and anaerobic conditions in municipal sewage sludge as a contribution toward understanding their environmental fate and behavior. MATERIALS AND METHODS: Bacterial communities from sewage sludge were exposed to a mixture of PFAS under aerobic or anaerobic conditions. Individual PFAS concentrations were determined in the experiment media at different exposure times using liquid chromatography-mass spectrometry analysis after extraction with solid-phase extraction. RESULTS: The PFAS analyses of samples of sludge showed repeatable replicate results, allowing a reliable quantification of the different groups of PFAS analyzed. No conclusive evidence for PFAS degradation was observed under the experimental conditions tested in this work. Reduction in concentrations, however, was observed for some PFAS in sludge under aerobic conditions. DISCUSSION: The largest concentration decrease occurred for the fluorotelomer alcohols (FTOHs), especially for the 8:2 FTOH, which have been described as biodegradable in the literature. However, this concentration decrease could be due to different causes: sorption to glass, septa, or matrix components, as well as bacterial activity. Therefore, it is not certain that biodegradation occurred. CONCLUSIONS: PFAS are very recalcitrant chemicals, especially when fully fluorinated. Although some decreases in concentration have been observed for some PFAS, such as the FTOHs, there is no conclusive evidence for biodegradation. It can be concluded that the PFAS tested in these experiments are non-biodegradable under these experimental conditions. RECOMMENDATIONS AND PERSPECTIVES: Since the presence of PFAS is ubiquitous in the environment and they can be toxic, more research is needed in this field to elucidate which PFAS are susceptible to biodegradation, the conditions required for biodegradation, and the possible routes followed. A possible inhibitory effect of PFAS on bacteria, the threshold concentrations, and conditions of inhibition should also be investigated.     

Identifying different types of bulking in an activated sludge system through quantitative image analysis

The present study proposes an image analysis methodology for the identification of different types of disturbances in wastewater treatment activated sludge systems. Up to date, most reported image analysis methodologies have been used in activated sludge processes with the aim of filamentous bulking detection, however, other disturbances could be foreseen in wastewater treatment plants. Such disturbances can lead to fluctuations in the biomass contents, affecting the mixed liquor suspended solids (MLSS), and in the sludge settling ability, affecting the sludge volume index (SVI). Therefore, this work focuses on predicting the MLSS and SVI parameters for different types of disturbances affecting an activated sludge system. Four experiments were conducted simulating filamentous bulking, zoogleal or viscous bulking, pinpoint floc formation, and normal operating conditions. Alongside the MLSS and SVI determination, the aggregated and filamentous biomass contents and morphology were studied as well as the biomass Gram and viability status, by means of image analysis.