微生物学通报  2019, Vol. 46 Issue (8): 1971−1981

扩展功能

文章信息

王萍, 余志晟
WANG Ping, YU Zhi-Sheng
污水处理厂污泥膨胀和污泥发泡的比较分析
Comparative analysis of sludge bulking and sludge foaming in wastewater treatment plant
微生物学通报, 2019, 46(8): 1971-1981
Microbiology China, 2019, 46(8): 1971-1981
DOI: 10.13344/j.microbiol.china.190310

文章历史

收稿日期: 2019-04-11
接受日期: 2019-06-05
网络首发日期: 2019-06-14
污水处理厂污泥膨胀和污泥发泡的比较分析
王萍1 , 余志晟2,3     
1. 周口师范学院化学化工学院    河南  周口    466001;
2. 中国科学院大学资源与环境学院    北京    100049;
3. RCEES-IMCAS-UCAS 环境微生物技术联合实验室    北京    100085
摘要: 活性污泥法由于操作简单、处理效果好被广泛应用于市政污水和工业废水的处理。污泥膨胀和污泥发泡现象影响二次沉淀池的泥水分离过程和生物反应池的微生物量稳定,严重困扰着污水处理厂的正常运行,被称为污水处理厂的“癌症”。本文从污泥膨胀和污泥发泡的定义及分类出发,全面地比较了表征污泥膨胀和污泥发泡的方法、引起污泥膨胀和污泥发泡的丝状细菌种类及控制污泥膨胀和污泥发泡方法的异同,并探讨了污泥膨胀和污泥发泡问题的未来研究方向和控制策略,期望能够为今后污泥膨胀和污泥发泡问题的研究和调控提供有价值的参考。
关键词: 污水处理厂    活性污泥工艺    污泥膨胀    污泥发泡    
Comparative analysis of sludge bulking and sludge foaming in wastewater treatment plant
WANG Ping1 , YU Zhi-Sheng2,3     
1. School of Chemistry and Chemical Engineering, Zhoukou Normal University, Zhoukou, Henan 466001, China;
2. 2 College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China;
3. 3 RCEES-IMCAS-UCAS Joint-Lab of Microbial Technology for Environmental Science, Beijing 100085, China
Abstract: Activated sludge (AS) process is the most widely process in wastewater treatment because of its simple operation and good treatment effect. Sludge bulking and sludge foaming, known as the "cancer" of wastewater treatment plants (WWTPs), affect the solid-liquid separation process of the secondary sedimentation tank and the stability of the microbial biomass in the biological reaction tank, which have long troubled the operation of WWTPs. The definition, classification, characterization methods, filamentous bacteria, and control methods of sludge bulking and sludge foaming were compared and analyzed as comprehensively as possible in this review. In addition, the future research direction and control strategy of sludge bulking and sludge foaming were discussed. It is expected to provide helpful information for future research on sludge bulking and sludge foaming.
Keywords: Wastewater treatment plant    Activated sludge process    Sludge bulking    Sludge foaming    

活性污泥法从发明至今已经有一百多年的历史。近几十年来,活性污泥法的生物反应和净化机理研究不断深入,使活性污泥法得到了较快的发展,出现了许多工艺,如吸附-生物降解工艺(A/B工艺)、厌氧-缺氧-好氧工艺(A2/O工艺)和序批式活性污泥工艺等,大大扩展了其适应范围[1]。活性污泥工艺由于处理效果好、操作简单、运行费用低等一系列的优点,被广泛地应用于市政污水和工业废水的处理。调查表明,国内外90%以上的城市污水都采用活性污泥法进行处理[2]。在我国已建成的污水处理厂中,超过85%的污水处理厂釆用活性污泥法,正在建设的城市污水处理厂几乎都采用活性污泥法工艺[3]。该工艺在市政污水和工业废水处理厂的应用极大地提高了污水的处理率,为实现水资源循环利用作出了卓越贡献。

活性污泥法的工艺流程主要包括两个部分:生化反应池和二次沉淀池。从生化反应池流出的泥水混合液必须在二次沉淀池进行充分的泥水分离,以保证二次沉淀池出水清澈;二次沉淀池沉下的污泥一部分必须要回流到生化反应池,以保证生化反应池中有稳定而充足的微生物量。因此,能够在生化反应池形成稳定、沉降性能好的絮体,进而在二次沉淀池进行充分的泥水分离是污水处理厂成功运行的基本条件。然而,从活性污泥法发明至今,污泥膨胀现象和污泥发泡现象便成为活性污泥工艺运行管理中的两大难题,一起被称为污水处理厂的“癌症”,影响着二次沉淀池的泥水分离过程和生物反应池微生物量的稳定[4-6]

对世界范围内污水厂的调查表明,不同的活性污泥法工艺均会发生污泥膨胀现象。澳大利亚被调查的65个污水处理厂中有53个发生污泥膨胀现象[7]。在丹麦和捷克,被调查的污水处理厂中超过50%受污泥膨胀现象的困扰[8-9]。在美国(338个)、法国(964个)和意大利(167个)的污水处理厂中,将近50%的污水处理厂会发生污泥膨胀现象[10-12]。与污泥膨胀现象相似,世界范围内不同的活性污泥法污水处理工艺均会发生污泥发泡现象。在美国北卡罗来纳州和伊利诺伊州分别有88%和97%的污水厂受到生物泡沫的困扰[13],在欧洲有20%的污水厂受到污泥发泡的影响,而采用延时曝气工艺的污水厂有87%受到污泥发泡的影响,并且50%的泡沫现象随季节循环出现[14]。在这些被调查的污水处理厂中,有时还会同时出现污泥膨胀现象和污泥发泡现象。例如,在澳大利亚昆士兰地区,有92%的污水厂受到污泥发泡的严重影响,这其中的60%同时还受到污泥膨胀的影响[15]。污水处理厂的污泥膨胀和污泥发泡现象联系密切又各有特点。本文基于活性污泥法污水处理厂污泥膨胀和污泥发泡现象的研究现状,从污泥膨胀和污泥发泡的危害、分类、表征方法、成因和控制方法等几个方面进行了比较分析,以期对污水处理厂污泥膨胀和污泥发泡现象的研究提供一些科学参考。

1 污泥膨胀和污泥发泡的定义、分类及危害(表 1)
表 1 污泥膨胀和污泥发泡的分类及特点 Table 1 The classification and characteristics of sludge bulking and sludge foaming
类别
Project
分类
Classification
类型
Type
发生原因
Occurrence reason
出现频率
Frequency
调控难易程度
The difficulty level of control
污泥膨胀
Sludge bulking
丝状菌膨胀
Filamentous bulking
丝状细菌膨胀
Filamentous bacteria bulking
丝状细菌的大量繁殖
The proliferation of filamentous bacteria

High

Difficult
丝状真菌膨胀
Filamentous fungi bulking
丝状真菌的大量繁殖
The proliferation of fungi bacteria

Low

Difficult
非丝状菌膨胀
Non-filamentous bulking
黏性膨胀
Viscous bulking
水温较低而负荷太高或者氮、磷缺乏,导致菌胶团菌大量累积高黏性物质
The accumulation of high-viscosity substances in zoogloea

Low
较易
Less easy
污泥发泡
Sludge foaming
生物发泡
Bio-foaming
丝状细菌发泡
Filamentous bacteria foaming
丝状细菌的过量繁殖而引起
The proliferation of filamentous bacteria

High
很难
More difficult
非生物发泡
Non-biofoaming
人工合成表面活性剂泡沫
Synthetic surfactant foam
启动过程中活性污泥对进水环境的不适应;工业污水中难降解表面活性剂
Driving foaming; Nondegradable surfactant in industrial wastewater

Low
较易
Less easy
反硝化泡沫
Denitrifying foam
反硝化过程中的含氮微气泡裹挟污泥
Nitrogen bind sludge during denitrification

Low

Easy

污泥膨胀是指污泥体积变大、含水率增高、在二次沉淀池不易沉淀的现象[16-18]。污泥膨胀总体上分为两大类:丝状菌膨胀和非丝状菌膨胀[18]。丝状菌膨胀是活性污泥絮体中的丝状细菌(偶尔是丝状真菌)过度繁殖而导致活性污泥沉降性能变差的现象;非丝状菌膨胀又称黏性膨胀或菌胶团膨胀,由菌胶团菌大量产生高黏性物质引起,是非丝状细菌过量而污泥沉降性能变差的现象[19],该现象主要在污水水温较低而污泥负荷太高或者进水中氮、磷等营养物缺乏的情况下发生[19]。当发生活性污泥膨胀时,污泥体积指数(SVI)升高(通常SVI值超过150即认为发生污泥膨胀现象),活性污泥絮体的结构比正常絮体松散,体积增大,含水率增高,澄清液变少。此外,由于在二次沉淀池不易沉淀,出水污泥含量增高,导致回流污泥量和生化反应池内污泥量减少,最终破坏生化反应池的正常运行[19]。在发生污泥膨胀的活性污泥法处理厂中,约有95%的污泥膨胀现象与活性污泥中丝状细菌的大量增殖有关[20]。丝状细菌污泥膨胀现象一旦发生,污泥的沉降性能在短时间内很难恢复。

污泥发泡是指大量泡沫出现在生化反应池和二次沉淀池,给活性污泥法污水处理厂的运行和处理效果带来负面影响的现象[20-21]。污泥发泡总体上也可以分为生物发泡和非生物发泡。污泥生物发泡是由于过度增殖的特定丝状细菌与污泥中的气泡和颗粒混合而形成稳定泡沫的现象。这种泡沫颜色呈棕色或灰褐色,非常粘稠,一般在生化反应池表面堆积,当污泥发泡严重时,会出现在二次沉淀池表面[20-21]。污泥非生物发泡主要是由于进水水质异常和操作异常而引起的污泥发泡现象,该现象发生时活性污泥中的丝状细菌无过度繁殖。目前在污水处理过程中发生的污泥非生物发泡现象可以分为两种类型:(1)人工合成表面活性剂泡沫。这种泡沫会出现在两种情况下。第一种情况是发生在含有难降解表面活性剂物质(比如烷基苯磺酸盐类物质)的工业污水处理厂中,微生物对这些表面活性剂的降解效率很低,导致大量泡沫出现在生化反应池和二次沉淀池[20]。由于环保意识的提高,易生物降解洗涤剂在日常生活中得到广泛推广,因此,目前这种泡沫很少出现。第二种情况是发生在活性污泥法污水处理厂运行初期的活性污泥培养阶段,接种微生物对市政污水中存在的各种表面活性物质的去除率较低,这时会有很多泡沫出现在生化反应池,该现象也称为启动泡沫[20]。这时的泡沫通常为白色,重量很轻,在活性污泥培育成熟之后,进水中有机污染物的去除率提高,这种泡沫便会消失。(2)反硝化泡沫。这种泡沫主要产生于二次沉淀池以及生化反应池的缺氧区。此区域存在的大量硝态氮容易发生反硝化作用,产生的含氮微气泡与污泥絮体聚集在一起,降低了污泥的密度,使污泥上浮。反硝化泡沫通常也是不稳定的,曝气和其它物理扰动都可以使其消失[20]。非生物发泡和生物发泡发生时,气泡都会携带着污泥上浮,使得泥水分离时的上层分离液变浑浊,导致二次沉淀池的出水不达标。在实际运行中,非生物发泡易得到控制,危害较小;而生物发泡现象一旦发生,一般会稳定长期存在,难以消除[20-21]。污泥生物发泡的危害主要表现在4个方面:(1)生物泡沫一般有一定的黏性,大量活性污泥会随其一起漂浮在生物反应池的表面,形成漂浮泡沫层,泡沫层会阻碍氧气进入生化反应池的混合液中,降低活性污泥的溶解氧含量。(2)泡沫浮渣层会进一步影响到二次沉淀池的泥水分离过程,从而导致二次沉淀池出水水质的恶化。(3)这些生物泡沫会飘落到工作通道上,影响设备巡检和维修。(4)生物泡沫可能存在病原微生物,具有随风传播的风险。

2 污泥膨胀和污泥发泡的表征方法(表 2)
表 2 污泥膨胀和污泥发泡的表征方法 Table 2 The characterization methods of sludge bulking and sludge foaming
表征方法
Characterization method
表征的现象
Phenomenon
操作难易程度
Ease of operation
评价效果优劣
Evaluation effect
SVI值
SVI value
丝状菌膨胀/非丝状菌膨胀现象
Bulking

Easy

Good
模拟曝气法
Simulated aeration
生物发泡/非生物发泡现象
Foaming
较易
Less easy

Bad
疏水性实验
Hydrophobic test
生物发泡/非生物发泡现象
Foaming
较易
Less easy

Bad
表面张力法
Surface tension method
生物发泡/非生物发泡现象
Foaming
较易
Less easy
一般
Average
目测法
Visual observation
生物发泡/非生物发泡现象
Foaming

Easy
一般
Average
丝状细菌检测法
Filamentous bacterial assay
生物发泡现象
Bio-foaming
较难
Less difficult

Good
浮渣指数评估法
Foam and scum index
生物发泡/非生物发泡现象
Foaming

Difficult

Good

对污泥膨胀和污泥发泡现象的表征是判断该类现象发生的依据及解决这些问题的基础,它们的表征方法显著不同。

污泥膨胀的表征方法比较确定。目前都是通过测定活性污泥的SVI值来评价污泥膨胀现象发生与否。一般情况下,沉降性能良好的活性污泥的SVI值在50-150之间,SVI值超过150即表征着该污水处理厂发生污泥膨胀现象。

目前,污泥发泡现象没有固定的表征方法。现有的一些表征方法各有优劣,具体有:(1)模拟曝气法。该方法是对量筒内的活性污泥进行模拟曝气,通过量筒中泡沫的体积变化以及泡沫的稳定时间进行污泥发泡分级。这种方法能在短时间内得到活性污泥的发泡潜能及泡沫稳定性的判断结果,但是这些结果并不能代表生物反应池的实际状态[22]。(2)细胞表面疏水性实验。该方法是将活性污泥中的微生物在水相和疏水相进行分配,通过测定处理前后水相吸光度判断活性污泥的发泡能力。这种方法对纯培养菌株的判定效果较好,实际活性污泥样品中的复杂物质很容易影响该测定过程[23]。(3)表面张力法。该方法是利用丝状细菌会引起活性污泥表面张力下降的特性,通过测定活性污泥表面张力的变化判断污泥发泡的潜能。与细胞疏水性实验相似,表面张力的测定同样容易受到污水中杂质的影响,导致结果不准确[24]。(4)目测法。基于操作者目测生化反应池和二次沉淀池表面的发泡情况,可以把污泥发泡分为4个发泡等级,从高到低依次是:1)严重的污泥发泡现象,泡沫在生化反应池和二次沉淀池表面分布明显;2)明显的污泥发泡现象,泡沫布满整个曝气池;3)污泥发泡现象开始或消失阶段,少量的泡沫在生化反应池;4)没有泡沫阶段。这种污泥发泡等级判断方法简单,但是由于没有活性污泥发泡潜能和稳定性的判断,误差较大[25]。(5)丝状细菌检测法。识别泡沫中丝状细菌的种类和含量判定活性污泥的发泡等级,研究表明,活性污泥泡沫层中富集了大量不同类型的丝状细菌,这些丝状细菌是引起污泥生物发泡的主要微生物。通过荧光原位杂交(Fluorescence in situ hybridization,FISH)技术鉴定泡沫中的丝状细菌类型和数量确定污泥发泡的生物成因是目前最流行的方法[26-28],这种方法可以较好地还原实际污泥和模拟状态下的微生物状态,也可以针对检测结果选择特异性的污泥发泡控制方法。但是这种方法需要一定的技术和实验设备支持,同时操作耗时。(6)泡沫浮渣指数(FSI)评估活性污泥发泡的等级。研究人员提出分析泡沫颜色、气泡大小、气泡稳定性、泡沫覆盖面积、丝状细菌类型、污泥气泡的潜能以及总悬浮固体含量等7个特征,并赋予其不同的权重,得到最终的FSI指数,这种方法虽然也较复杂,但是评价指数覆盖面广,FSI指数高低与污泥发泡等级有较好的线性相关关系[23]

3 引起污泥膨胀和污泥发泡的丝状细菌

Eikelboom等最早发明了传统的丝状细菌分类方法,这种方法主要是通过微生物细胞的大小形态、染色反应、菌丝形态、分布位置、附着细菌类型、细胞间鞘隔膜等繁杂而精细的步骤进行[21, 26, 29]。Eikelboom等按照此方法从市政污水厂中识别到30多种不同类型的丝状细菌,为污泥膨胀和污泥发泡现象的研究作出了巨大贡献。然而,同种生物在不同培养状态下会出现形态差异,而亲缘关系差异巨大的微生物也可能表现出相同的形态,这些现象导致即使是经验丰富的科研人员也很难根据传统分类方法鉴定丝状细菌[14, 30-31]。加之污泥中许多微生物还属于未培养之列,更增加了传统分类的难度。目前,各种分子生物技术,如FISH、高通量测序技术、宏基因组测序技术等发展迅速,为及时、全面和准确地获取污泥中丝状细菌的基因信息提供了很大帮助,促进了丝状细菌的进一步分类[32-34]。Guo等对引起活性污泥沉降问题的丝状细菌的16S rRNA基因序列进行了系统的整理,并建立了丝状细菌(Bulking and foaming bacteria)的数据库[35-36]。大量的研究结果显示,不同丝状细菌的过度增殖均可造成污泥膨胀现象[37-38],而污泥发泡现象只与两类丝状细菌的增殖有关[14, 38-39]。下面分别介绍引起污泥发泡和污泥膨胀现象的丝状细菌类型。

3.1 引起污泥膨胀的丝状细菌类型

Nielsen等已经非常详细地描述了活性污泥系统中存在的丝状细菌,如变形菌门、绿弯菌门和放线菌门等,并详细地介绍了与污泥膨胀现象有关的丝状细菌类型及其纯培养下的生理生化特征[14]。工业废水处理厂的污泥膨胀现象经常与α-变形菌纲丝状细菌(如Meganema perideroedes)的过度繁殖有关[40]。纤毛菌属(Leptothrix)和Curvibacter属的丝状细菌属于β-变形菌纲,也普遍存在于污泥膨胀过程中[14]。γ-变形菌纲的丝状细菌如丝硫细菌属(Thiothrix)、贝日阿托菌属(Beggiatoa)、亮发菌属(Leucothrix)的大量增殖也会引起污泥膨胀现象[14]。绿弯菌门的丝状细菌,如Type 0803、Type 0914和Type 1851等,通常在活性污泥处理系统污水处理厂中出现,它们的大量增殖会引起污泥膨胀现象[41-43]。放线菌门中引起污泥膨胀的丝状细菌通常有三类:微丝菌(Candidatus Microthrix parvicella)、诺卡氏型丝状细菌(Nocardioform)和Tetrasphaera属的丝状细菌。目前的研究表明,Candidatus Microthrix parvicella和诺卡氏型丝状细菌不但能引起污泥膨胀现象,还可引起污泥发泡现象。Tetrasphaera属的丝状细菌在活性污泥系统中也经常存在,但是数量很少,该属的丝状细菌能在有氧、缺氧和厌氧条件下吸收长链脂肪酸类的疏水性物质,这使其在污泥膨胀时期占据优势生态位[14]。此外,拟杆菌门丝状细菌和厚壁菌门丝状细菌的过度增殖也有引起污泥膨胀的潜能[14]

3.2 引起污泥发泡的丝状细菌

引起污泥生物发泡现象的丝状细菌主要有两种,分别是Nocardioform型丝状细菌和微Candidatus Microthrix parvicella型丝状细菌。

3.2.1 Nocardioform型丝状细菌

Nocardioform型丝状细菌是早期污水处理厂工作者日常监测中的习惯性称法,主要指可以通过显微镜看到的具有放线状外观的一类异养好氧、具有明显真分枝的革兰氏阳性细菌。由于这一类微生物的细胞壁都富含脂质(主要是分枝菌酸)并且具有高度疏水性,因此这一类丝状细菌也叫Mycolata[44-46]。按照遗传亲缘关系进行划分,目前发现的诺卡氏型丝状细菌包括了NocardiaGordoniaRhodococcusSkermaniaCorynebacteriumDietziaTsukamurellaWilliamsia以及Mycobacterium等11个属[44, 47-48]Gordonia amarae是最早发现的诺卡氏型丝状细菌,研究表明它在澳大利亚、中国香港、美国加州等地是主要致污泥发泡现象的微生物[49-51]。现有的生理生态数据表明诺卡氏型丝状细菌具有非常高的储存营养物质的能力,这可能是其能够在泡沫这种营养限制环境中生存的原因[52-54]。诺卡氏型丝状细菌可以利用多种形态的碳源、氮源和磷源,当污水中含有丰富的疏水性营养物质时,诺卡氏型丝状细菌的这种竞争优势更加明显[55-57]

3.2.2 Candidatus Microthrix parvicella型

Candidatus Microthrix parvicella是另一类已经被证明会引起污泥发泡现象的革兰氏阳性丝状细菌[58-59],是放线菌门放线菌纲中一个进化独立的类群[60]。这一类型丝状细菌的细胞壁中不含分枝菌酸,但是表面具有高度疏水性,使其可以水解、摄取并生长在脂质类物质上[61-63]。此外,Candidatus Microthrix parvicella对高氧浓度胁迫敏感,更适合在微氧环境下生长[13]。在澳大利亚、英国和中国的污水处理厂中,Candidatus Microthrix parvicella都是引起污泥发泡现象的优势丝状细菌[64-66]

4 控制方法(表 3)
表 3 污泥膨胀和污泥发泡的控制方法 Table 3 The control methods of sludge bulking and sludge foaming
控制方法
Control method
分类
Classification
效果
Effect
能耗
Energy consumption
环境友好程度*
Environmental friendliness*
非特异性方法
Nonspecific method
物理方法
Physical method
不好
Bad

High
不友好
Unfriendly
化学方法
Chemical method
不好
Bad

High
不友好
Unfriendly
特异性方法
Specific method
操作过程调控
Operation process control
较好
Less good
较高
Less high
较友好
Less friendly
选择器
Selector

Good
较高
Less high
较友好
Less friendly
生态调控
Ecological control

Good

Low
友好
Friendly
注:*:环境友好程度的评价主要从能耗高低和是否引入新的污染物两个角度衡量.
Note: *: The evaluation of friendliness is mainly from the two aspects of energy consumption and whether to introduce new pollutants.

目前,对污泥膨胀现象和污泥发泡现象的调控思路比较相似,主要分为两大类。第一类是非特异性方法,采用物理化学的方法调控污泥发泡和污泥膨胀;第二类方法是特异性方法,先通过分子生物学方法解析活性污泥微生物生态以确定引起污泥发泡的丝状细菌类型,通过改变操作条件、增加选择器或者引入其它物种调控该类丝状细菌的增殖,以达到控制污泥膨胀和污泥发泡现象的目的。

4.1 非特异性方法

4.1.1 物理方法

污泥发泡的危害很大程度上来源于其泡沫层,因此可以采用喷洒水及人工或机械清理泡沫层的物理方法调控污泥发泡现象。喷洒水是一种简单的物理方法,但是被水喷散的泡沫仍然存在于混合液中,所以不能根本消除泡沫现象。通过人工或机械将泡沫打捞清除会增加生产成本,后续如何处置这些生物泡沫仍是很大的难题[8]。类似物理性方法不能用于污泥膨胀现象的控制。

4.1.2 化学方法

调控丝状细菌引起的污泥膨胀和污泥发泡现象的化学方法主要包括投加氧化剂和消毒剂或者混凝剂。投加的氧化剂和消毒剂主要有氯、次氯酸、过氧化氢、臭氧、季铵盐等。由于引起污泥膨胀和污泥发泡现象的丝状细菌具有独特的分散形态特征,使得其在活性污泥中暴露的比表面积大于其它菌胶团菌暴露的比表面积,当使用氧化剂进行杀菌时,暴露多的丝状细菌能优先被杀灭。从经济性的角度考虑,目前比较常用的氧化剂为氯气或次氯酸钠溶液,氯气投加量为1-15 g/(kg·d)[67]。但大部分丝状细菌细胞表面的疏水性都比较强,导致氯难以渗透到这些疏水性丝状细菌的细胞质中,影响其对丝状细菌的杀灭效果。如果加大氯的投加量,不但不会提高对疏水性丝状细菌的杀菌效果,还会影响菌胶团菌的功能。在以高达20 g/(kg·d)的剂量下投加氯时,Candidatus Microthrix parvicella没有受到抑制,但对菌胶团菌的功能产生了较大影响[68]。除了氯剂杀菌,臭氧和过氧化氢也用于控制丝状细菌引起的污泥膨胀和污泥发泡现象。臭氧的投加量通常比氯气的投加量低,用量为0.001 6-6.6 g/(kg·d)[69-71]。臭氧和过氧化氢的优势还在于杀菌时不会在水中残留副产物,且对菌胶团菌的影响相对较轻,但其缺点为成本较高。投加混凝剂主要包括聚丙烯酰胺、聚合氯化铝(PAX)、氯化亚铁、氯化铁等。絮凝剂的主要作用机理是改变絮体结构优化活性污泥沉降性。研究表明,铝盐和铁盐絮凝剂的投加对Candidatus Microthrix parvicella诱导的污泥膨胀现象有较好的控制效果[58, 72-73]。研究还表明,通过向实际污水厂添加聚丙烯酰胺、铝盐和铁盐絮凝剂能有效地控制丝状细菌(如RhodococcusGordonia amarae)引起的污泥发泡现象[74-76]

这些非特异性的控制方法有时可以起到立竿见影的效果,但是由于导致污泥膨胀和污泥发泡的关键因素并没有消除,所以这种效果只是暂时性的。一旦这些物理和化学方法停止,污泥膨胀和污泥发泡现象还会发生。

4.2 特异性方法

特异性技术是指针对关键丝状细菌的优势生长因子进行有选择性地消除并控制致污泥膨胀和污泥发泡现象的策略与方式。

4.2.1 操作过程调控

操作过程调控的思路是先确定引起污泥膨胀和污泥发泡的丝状细菌类型,再调控各种操作因子和环境因子降低该类丝状细菌的竞争生长优势,以达到抑制该类丝状细菌增殖的目的。例如,模拟实验发现,当污泥负荷低时,Candidatus Microthrix parvicella呈现竞争生长优势,当把污泥负荷增加到一定程度,污泥沉降性能显著改善[77]。此外,研究还表明,Candidatus Microthrix parvicella具有耐寒特性,当污泥混合液的温度在12-15 ℃维持一段时间后,会发生由其主导的污泥发泡和污泥膨胀现象[78]。因此,可以通过改变活性污泥的温度、溶解氧和有机负荷等因素控制由Candidatus Microthrix parvicella引起的污泥膨胀和污泥发泡现象。

4.2.2 选择器

选择器(Selector)是一个混合池或通道,是生物反应池的初始部分,从二次沉淀池回流的污泥进入曝气池前先流经选择器进行特定的选择[79]。选择器可分为好氧、缺氧和厌氧3种类型,在选择器中可以通过有机物负荷、溶解氧、电子受体等多种条件抑制特定丝状菌的过度增长[20]。好氧型选择器对于Type021N、丝硫细菌和浮游球衣细菌等丝状细菌的控制效果较好[80]。而厌氧型选择器对Candidatus Microthrix parvicella的控制效果较好[81]

4.2.3 生物调控

活性污泥中的各种微生物通过捕食、竞争、共生等关系组合成一个复杂的生态系统。生态调控的思路是根据该生态系统中各生物之间的关系调控关键丝状细菌的增殖,以达到调控污泥膨胀和污泥发泡现象的目的。噬菌体能够入侵并裂解宿主细胞,因此可以作为生物工具使用[82]。目前已经分离到不同类型的烈性噬菌体细胞,可以裂解GordoniaNocardiaRhodococcus等属的丝状细菌等[83-85]。此外,有研究通过原生动物或后生动物对丝状细菌的捕食作用来消除污泥膨胀和污泥发泡问题。Pajdak-Stós等发现Lecane tenuisetaLecane inermisLecane pyriformis等轮虫可以显著抑制Candidatus Microthrix parvicella和Type 0092丝状细菌的生长[86],不同种类轮虫捕食的丝状菌类型不同,其中利用Lecane inermis在实际污水厂持续一年的实验结果表明其显著降低了Candidatus Microthrix parvicella和诺卡氏型丝状细菌在活性污泥中的含量[86]

5 展望

(1) 在未来的研究中,可以进一步利用不断发展的分子生物学技术和微生物单细胞分离技术确定不同污水处理厂污泥膨胀和污泥发泡现象发生的关键丝状细菌,得到这些丝状细菌的纯培养菌株并研究其生理生化特性,为污泥膨胀和污泥发泡现象的控制提供理论基础。

(2) 基于生态学方法调控污泥膨胀和污泥发泡现象是一种生态友好的调控方法,有着广阔的发展前景。虽然目前研究表明可以通过在活性污泥中引入噬菌体或轮虫达到控制丝状细菌增殖的目的,但仍需深入系统地研究才能在实际污水处理厂进行推广应用。

(3) 本文作者对污泥膨胀和污泥发泡的研究表明,在污泥膨胀和污泥发泡周期内,随着引起污泥膨胀和污泥发泡的关键丝状细菌Candidatus Microthrix parvicella的增殖,氮代谢功能菌的丰度和种类显著减少。这一结果表明在污泥膨胀和污泥发泡过程中Candidatus Microthrix parvicella和氮代谢功能菌之间存在竞争关系。根据生态学原理,除了可以在活性污泥中选择引入丝状细菌的噬菌体和丝状细菌的捕食者控制丝状细菌引起的污泥膨胀和污泥发泡现象,还可以通过引入丝状细菌的竞争者来控制丝状细菌的增殖。本文作者正在研究通过调控活性污泥中氮代谢功能菌的组成和数量对Candidatus Microthrix parvicella增殖的抑制效果。

参考文献
[1]
Jenkins D, Wanner J. Activated Sludge-100 Years and Counting[M]. London: IWA Publishing, 2014.
[2]
Li ZR. Research on the microbial characteristics of enhancing the aerobic digestion of excess sludge[D]. Beijing: Master's Thesis of Beijing University of Chemical Technology, 2014 (in Chinese)
李再然.微生物强化剩余污泥好氧消化的过程研究[D].北京: 北京化工大学硕士学位论文, 2014 http://cdmd.cnki.com.cn/Article/CDMD-10010-1015544456.htm
[3]
Li X. Microbial pretreatment on dewatered sludge and optimization of anaerobic digestion process performance[D]. Beijing: Doctoral Dissertation of China Agricultural University, 2015 (in Chinese)
李雪.微生物法预处理污泥厌氧消化过程性能优化研究[D].北京: 中国农业大学博士学位论文, 2015 http://cdmd.cnki.com.cn/Article/CDMD-10019-1015584280.htm
[4]
Kunst S, Reins M. Practical investigations on bulking and foaming in activated sludge plants with biological phosphorus removal[J]. Water Science & Technology, 1994, 29(7): 289-294.
[5]
Mielczarek AT, Kragelund C, Eriksen PS, et al. Population dynamics of filamentous bacteria in Danish wastewater treatment plants with nutrient removal[J]. Water Research, 2012, 46(12): 3781-3795. DOI:10.1016/j.watres.2012.04.009
[6]
Pujol R, Duchene, Schetrite S, et al. Biological foams in activated sludge plants: Characterization and situation[J]. Water Research, 1991, 25(11): 1399-1404. DOI:10.1016/0043-1354(91)90118-A
[7]
Seviour EM, Williams C, DeGrey B, et al. Studies on filamentous bacteria from australian activated sludge plants[J]. Water Research, 1994, 28(11): 2335-2342. DOI:10.1016/0043-1354(94)90049-3
[8]
Wanner J, Ruzicková I, Jetmarová P, et al. A national survey of activated sludge separation problems in the Czech Republic: filaments, floc characteristics and activated sludge metabolic properties[J]. Water Science and Technology, 1998, 37(4/5): 271-279.
[9]
Kristensen GH, Jørgensen PE, Nielsen PH. Settling characteristics of activated sludge in danish treatment plants with biological nutrient removal[J]. Water Science & Technology, 1994, 29(7): 157-165.
[10]
Madoni P, Davoli D, Gibin G. Survey of filamentous microorganisms from bulking and foaming activated-sludge plants in Italy[J]. Water Research, 2000, 34(6): 1767-1772. DOI:10.1016/S0043-1354(99)00352-8
[11]
Graveleau L, Cotteux E, Duchène P. Bulking and foaming in France: the 1999-2001 survey[J]. Acta Hydrochimica et Hydrobiologica, 2005, 33(3): 223-231. DOI:10.1002/aheh.200400566
[12]
Strom PF, Jenkins D. Identification and significance of filamentous microorganisms in activated sludge[J]. Journal (Water Pollution Control Federation), 1984, 56(5): 449-459.
[13]
Rossetti S, Tomei MC, Nielsen PH, et al. "Microthrix parvicella", a filamentous bacterium causing bulking and foaming in activated sludge systems: a review of current knowledge[J]. FEMS Microbiology Reviews, 2010, 29(1): 49-64.
[14]
Nielsen PH, Kragelund C, Seviour RJ, et al. Identity and ecophysiology of filamentous bacteria in activated sludge[J]. FEMS Microbiology Reviews, 2009, 33(6): 969-998. DOI:10.1111/j.1574-6976.2009.00186.x
[15]
Xia Y, Wen XH, Zhang B, et al. Diversity and assembly patterns of activated sludge microbial communities: a review[J]. Biotechnology Advances, 2018, 36(4): 1038-1047. DOI:10.1016/j.biotechadv.2018.03.005
[16]
Miłobędzka A, Muszyński A. Population dynamics of filamentous bacteria identified in Polish full-scale wastewater treatment plants with nutrients removal[J]. Water Science & Technology, 2014, 71(5): 675-684.
[17]
Speirs LBM, Mcilroy SJ, Petrovski S, et al. The activated sludge bulking filament Eikelboom morphotype 0914 is a member of the Chloroflexi[J]. Environmental Microbiology Reports, 2011, 3(2): 159-165. DOI:10.1111/j.1758-2229.2010.00201.x
[18]
Novák L, Larrea L, Wanner J, et al. Non-filamentous activated sludge bulking in a laboratory scale system[J]. Water Research, 1993, 27(8): 1339-1346. DOI:10.1016/0043-1354(93)90221-3
[19]
Chen Y, Peng YZ, Liu M, et al. Non-filamentous activated sludge bulking in SBR treating the domestic wastewater[J]. Acta Scientiae Circumstantiae, 2005, 25(1): 105-108. (in Chinese)
陈滢, 彭永臻, 刘敏, 等. SBR法处理生活污水时非丝状菌污泥膨胀的发生与控制[J]. 环境科学学报, 2005, 25(1): 105-108. DOI:10.3321/j.issn:0253-2468.2005.01.019
[20]
Sezgin M, Jenkins D, Parker DS. A unified theory of filamentous activated sludge bulking[J]. Journal (Water Pollution Control Federation), 1978, 50(2): 362-381.
[21]
Jenkins D, Richard MG, Daigger GT. Manual on the Causes and Control of Activated Sludge Bulking, Foaming, and Other Solids Separation Problems[M]. 3rd ed. London: CRC Press, 2003.
[22]
Blackall LL, Harbers AE, Greenfield PF, et al. Activated sludge foams: Effects of environmental variables on organism growth and foam formation[J]. Environmental Technology, 1991, 12(3): 241-248. DOI:10.1080/09593339109385001
[23]
Hladikova K, Ruzickova I, Klucova P, et al. An investigation into studying of the activated sludge foaming potential by using physicochemical parameters[J]. Water Science & Technology, 2002, 46(1/2): 525-528.
[24]
Pagilla KR, Sood A, Kim H. Gordonia (Nocardia) amarae foaming due to biosurfactant production[J]. Water Science & Technology, 2002, 46(1/2): 519-524.
[25]
Frigon D, Guthrie RM, Bachman GT, et al. Long-term analysis of a full-scale activated sludge wastewater treatment system exhibiting seasonal biological foaming[J]. Water Research, 2006, 40(5): 990-1008. DOI:10.1016/j.watres.2005.12.015
[26]
Eikelboom DH. Filamentous organisms observed in activated sludge[J]. Water Research, 1975, 9(4): 365-388. DOI:10.1016/0043-1354(75)90182-7
[27]
Wagner M, Amann R, Kämpfer P, et al. Identification and in situ detection of gram-negative filamentous bacteria in activated sludge[J]. Systematic and Applied Microbiology, 1994, 17(3): 405-417. DOI:10.1016/S0723-2020(11)80058-5
[28]
Kumari SKS, Marrengane Z, Bux F. Application of quantitative RT-PCR to determine the distribution of Microthrix parvicella in full-scale activated sludge treatment systems[J]. Applied Microbiology and Biotechnology, 2009, 83(6): 1135-1141. DOI:10.1007/s00253-009-2013-9
[29]
Eikelboom DH. Process Control of Activated Sludge Plants by Microscopic Investigation[M]. London: IWA Publishing, 2000.
[30]
Asvapathanagul P, Huang ZH, Gedalanga PB, et al. Interaction of operational and physicochemical factors leading to Gordonia amarae-like foaming in an incompletely nitrifying activated sludge plant[J]. Applied and Environmental Microbiology, 2012, 78(23): 8165-8175. DOI:10.1128/AEM.00404-12
[31]
Nielsen PH, Daims H, Lemmer H, et al. FISH Handbook for Biological Wastewater Treatment[M]. London: IWA Publishing, 2009.
[32]
Ju F, Guo F, Ye L, et al. Metagenomic analysis on seasonal microbial variations of activated sludge from a full-scale wastewater treatment plant over 4 years[J]. Environmental Microbiology Reports, 2014, 6(1): 80-89. DOI:10.1111/1758-2229.12110
[33]
Dunkel T, de León Gallegos EL, Bock C, et al. Illumina sequencing for the identification of filamentous bulking and foaming bacteria in industrial activated sludge plants[J]. International Journal of Environmental Science and Technology, 2018, 15(6): 1139-1158. DOI:10.1007/s13762-017-1484-y
[34]
Jiang XT, Ye L, Ju F, et al. Toward an intensive longitudinal understanding of activated sludge bacterial assembly and dynamics[J]. Environmental Science & Technology, 2018, 52(15): 8224-8232.
[35]
Jiang XT, Guo F, Zhang T. Population dynamics of bulking and foaming bacteria in a full-scale wastewater treatment plant over five years[J]. Scientific Reports, 2016, 6: 24180. DOI:10.1038/srep24180
[36]
Guo F, Zhang T. Profiling bulking and foaming bacteria in activated sludge by high throughput sequencing[J]. Water Research, 2012, 46(8): 2772-2782. DOI:10.1016/j.watres.2012.02.039
[37]
Andreasen K, Sigvardsen L. Experiences with sludge settleability in different process alternatives for nutrient removal[J]. Water Science & Technology, 1996, 33(12): 137-146.
[38]
Wang P, Yu ZS, Qi R, et al. Detailed comparison of bacterial communities during seasonal sludge bulking in a municipal wastewater treatment plant[J]. Water Research, 2016, 105: 157-166. DOI:10.1016/j.watres.2016.08.050
[39]
Maza-Márquez P, Gómez-Silván C, Gómez MA, et al. Linking operation parameters and environmental variables to population dynamics of Mycolata in a membrane bioreactor[J]. Bioresource Technology, 2015, 180: 318-329. DOI:10.1016/j.biortech.2014.12.081
[40]
Kurisu F, Zang K, Kasuga I, et al. Identification of estrone-degrading Betaproteobacteria in activated sludge by microautoradiography fluorescent in situ hybridization[J]. Letters in Applied Microbiology, 2015, 61(1): 28-35. DOI:10.1111/lam.12407
[41]
Wang P, Yu ZS, Zhao JH, et al. Seasonal changes in bacterial communities cause foaming in a wastewater treatment plant[J]. Microbial Ecology, 2016, 71(3): 660-671. DOI:10.1007/s00248-015-0700-x
[42]
Speirs LBM, Tucci J, Seviour RJ. The activated sludge bulking filament Eikelboom morphotype 0803 embraces more than one member of the Chloroflexi[J]. FEMS Microbiology Ecology, 2015, 91(9): fiv100. DOI:10.1093/femsec/fiv100
[43]
Nittami T, Speirs LBM, Yamada T, et al. Quantification of Chloroflexi Eikelboom morphotype 1851 for prediction and control of bulking events in municipal activated sludge plants in Japan[J]. Applied Microbiology and Biotechnology, 2017, 101(9): 3861-3869. DOI:10.1007/s00253-016-8077-4
[44]
Davenport RJ, Pickering RL, Goodhead AK, et al. A universal threshold concept for hydrophobic Mycolata in activated sludge foaming[J]. Water Research, 2008, 42(13): 3446-3454. DOI:10.1016/j.watres.2008.02.033
[45]
Goodfellow M, Stainsby FM, Davenport R, et al. Activated sludge foaming: the true extent of actinomycete diversity[J]. Water Science and Technology, 1998, 37(4/5): 511-519.
[46]
Soddell JA, Seviour RJ. Microbiology of foaming in activated sludge plants[J]. Journal of Applied Bacteriology, 1990, 69(2): 145-176. DOI:10.1111/j.1365-2672.1990.tb01506.x
[47]
Lechevalier MP, Lechevalier HA. Nocardia amarae sp. nov., an actinomycete common in foaming activated sludge[J]. International Journal of Systematic and Evolutionary Microbiology, 1974, 24(2): 278-288.
[48]
Chun J, Blackall LL, Kang SO, et al. A proposal to reclassify Nocardia pinensis Blackall et al. as Skermania piniformis gen. nov., comb. nov[J]. International Journal of Systematic and Evolutionary Microbiology, 1997, 47(1): 127-131.
[49]
Pitt P, Jenkins D. Causes and control of Nocardia in activated sludge[J]. Research Journal of the Water Pollution Control Federation, 1990, 62(2): 143-150.
[50]
Blackall LL, Harbers AE, Greenfield PF, et al. Foaming in activated sludge plants: a survey in Queensland, Australia and an evaluation of some control strategies[J]. Water Research, 1991, 25(3): 313-317. DOI:10.1016/0043-1354(91)90011-E
[51]
Guo F, Wang ZP, Yu K, et al. Detailed investigation of the microbial community in foaming activated sludge reveals novel foam formers[J]. Scientific Reports, 2015, 5: 7637. DOI:10.1038/srep07637
[52]
Eales K, Nielsen JL, Kragelund C, et al. The in situ physiology of Pine Tree Like Organisms (PTLO) in activated sludge foams[J]. Acta Hydrochimica et Hydrobiologica, 2005, 33(3): 203-209. DOI:10.1002/aheh.200400571
[53]
Eales KL, Nielsen JL, Seviour EM, et al. The in situ physiology of Skermania piniformis in foams in Australian activated sludge plants[J]. Environmental Microbiology, 2006, 8(10): 1712-1720. DOI:10.1111/j.1462-2920.2006.01107.x
[54]
Wong MT, Mino T, Seviour RJ, et al. In situ identification and characterization of the microbial community structure of full-scale enhanced biological phosphorous removal plants in Japan[J]. Water Research, 2005, 39(13): 2901-2914. DOI:10.1016/j.watres.2005.05.015
[55]
Lemmer H, Lind G, Schade M, et al. Autecology of scum producing bacteria[J]. Water Science and Technology, 1998, 37(4/5): 527-530.
[56]
Stratton H, Seviour B, Brooks P. Activated sludge foaming: what causes hydrophobicity and can it be manipulated to control foaming[J]. Water Science and Technology, 1998, 37(4/5): 503-509.
[57]
Lemmer H, Baumann M. Scum actinomycetes in sewage treatment plants-Part 3: synergisms with other sludge bacteria[J]. Water Research, 1988, 22(6): 765-767. DOI:10.1016/0043-1354(88)90188-1
[58]
Durban N, Juzan L, Krier J, et al. Control of Microthrix parvicella by aluminium salts addition[J]. Water Science & Technology, 2015, 73(2): 414-422.
[59]
Xie B, Dai XC, Xu YT. Cause and pre-alarm control of bulking and foaming by Microthrix parvicella-A case study in triple oxidation ditch at a wastewater treatment plant[J]. Journal of Hazardous Materials, 2007, 143(1/2): 184-191.
[60]
Blackall LL, Seviour EM, Bradford D, et al. Towards understanding the taxonomy of some of the filamentous bacteria causing bulking and foaming in activated sludge plants[J]. Water Science and Technology, 1996, 34(5/6): 137-144.
[61]
Nielsen PH, Roslev P, Dueholm TE, et al. Microthrix parvicella, a specialized lipid consumer in anaerobic-aerobic activated sludge plants[J]. Water Science & Technology, 2002, 46(1/2): 73-80.
[62]
Tandoi V, Rossetti S, Blackall LL, et al. Some physiological properties of an Italian isolate of "Microthrix parvicella"[J]. Water Science and Technology, 1998, 37(4/5): 1-8.
[63]
Slijkhuis H. Microthrix parvicella, a filamentous bacterium isolated from activated sludge: cultivation in a chemically defined medium[J]. Applied and Environmental Microbiology, 1983, 46(4): 832-839.
[64]
Khan AR, Kocianova E, Forster CF. Activated sludge characteristics in relation to stable foam formation[J]. Journal of Chemical Technology and Biotechnology, 1991, 52(3): 383-392.
[65]
Seviour EM, Williams CJ, Seviour RJ, et al. A survey of filamentous bacterial populations from foaming activated sludge plants in eastern states of Australia[J]. Water Research, 1990, 24(4): 493-498. DOI:10.1016/0043-1354(90)90234-W
[66]
Kragelund C, Kong Y, van der Waarde J, et al. Ecophysiology of different filamentous Alphaproteobacteria in industrial wastewater treatment plants[J]. Microbiology, 2006, 152(10): 3003-3012. DOI:10.1099/mic.0.29249-0
[67]
Madoni P, Davoli D. Testing the control of filamentous microorganisms responsible for foaming in a full-scale activated-sludge plant running with initial aerobic or anoxic contact zones[J]. Bioresource Technology, 1997, 60(1): 43-49. DOI:10.1016/S0960-8524(96)00151-4
[68]
Hwang Y, Tanaka T. Control of Microthrix parvicella foaming in activated sludge[J]. Water Research, 1998, 32(5): 1678-1686. DOI:10.1016/S0043-1354(97)00380-1
[69]
Lyko S, Teichgräber B, Kraft A. Bulking control by low-dose ozonation of returned activated sludge in a full-scale wastewater treatment plant[J]. Water Science & Technology, 2012, 65(9): 1654-1661.
[70]
Levén L, Wijnbladh E, Tuvesson M, et al. Control of Microthrix parvicella and sludge bulking by ozone in a full-scale WWTP[J]. Water Science & Technology, 2016, 73(4): 866-872.
[71]
Chu LB, Wang JL, Wang B, et al. Changes in biomass activity and characteristics of activated sludge exposed to low ozone dose[J]. Chemosphere, 2009, 77(2): 267-272.
[72]
Roels T, Dauwe F, van Damme S, et al. The influence of PAX-14 on activated sludge systems and in particular on Microthrix parvicella[J]. Water Science & Technology, 2002, 46(1/2): 487-490.
[73]
Paris S, Lind G, Lemmer H, et al. Dosing aluminum chloride to control Microthrix parvicella[J]. Acta Hydrochimica et Hydrobiologica, 2005, 33(3): 247-254. DOI:10.1002/aheh.200400577
[74]
Mamais D, Kalaitzi E, Andreadakis A. Foaming control in activated sludge treatment plants by coagulants addition[J]. Global Nest Journal, 2011, 13(3): 237-245.
[75]
Shao YJ, Starr M, Kaporis K, et al. Polymer addition as a solution to Nocardia foaming problems[J]. Water Environment Research, 1997, 69(1): 25-27. DOI:10.2175/106143097X125146
[76]
Lemmer H, Kroppensted RM. Chemotaxonomy and physiology of some actinomycetes isolated from scumming activated sludge[J]. Systematic and Applied Microbiology, 1984, 5(1): 124-135. DOI:10.1016/S0723-2020(84)80057-0
[77]
Fan NS, Qi R, Rossetti S, et al. Factors affecting the growth of Microthrix parvicella: batch tests using bulking sludge as seed sludge[J]. Science of the Total Environment, 2017, 609: 1192-1199. DOI:10.1016/j.scitotenv.2017.07.261
[78]
Rossetti S, Tomei MC, Nielsen PH, et al. "Microthrix parvicella", a filamentous bacterium causing bulking and foaming in activated sludge systems: a review of current knowledge[J]. FEMS Microbiology Reviews, 2005, 29(1): 49-56. DOI:10.1016/j.femsre.2004.09.005
[79]
Pal P, Khairnar K, Paunikar WN. Causes and remedies for filamentous foaming in activated sludge treatment plant[J]. Global Nest Journal, 2014, 16(4): 762-772. DOI:10.30955/gnj.001273
[80]
Daigger GT, Robbins MH, Marshall Jr BR. The design of a selector to control low-F/M filamentous bulking[J]. Journal (Water Pollution Control Federation), 1985, 57(3): 220-226.
[81]
Kruit J, Hulsbeek J, Visser A. Bulking sludge solved?![J]. Water Science & Technology, 2002, 46(1/2): 457-464.
[82]
Thomas JA, Soddell JA, Kurtböke DI. Fighting foam with phages?[J]. Water Science & Technology, 2002, 46(1/2): 511-518.
[83]
Dyson ZA, Tucci J, Seviour RJ, et al. Isolation and characterization of bacteriophage SPI1, which infects the activated-sludge-foaming bacterium Skermania piniformis[J]. Archives of Virology, 2016, 161(1): 149-158. DOI:10.1007/s00705-015-2631-8
[84]
Khairnar K, Pal P, Chandekar RH, et al. Isolation and characterization of bacteriophages infecting nocardioforms in wastewater treatment plant[J]. Biotechnology Research International, 2014, 2014: 151952.
[85]
Dyson ZA, Brown TL, Farrar B, et al. Locating and activating molecular 'time bombs': Induction of Mycolata prophages[J]. PLoS One, 2016, 11(8): e0159957. DOI:10.1371/journal.pone.0159957
[86]
Pajdak-Stós A, Kocerba-Soroka W, Fyda J, et al. Foam-forming bacteria in activated sludge effectively reduced by rotifers in laboratory- and real-scale wastewater treatment plant experiments[J]. Environmental Science and Pollution Research, 2017, 24(14): 13004-13011. DOI:10.1007/s11356-017-8890-z