微丝菌培养分离、特性标记及调控研究进展

污泥膨胀一直是困扰污水处理厂正常运行的一个世界性难题,而微丝菌是污泥丝状膨胀中的主要丝状菌,因此对微丝菌本质规律的研究不仅有利于认识微丝菌,也可提供诸多控制污泥丝状膨胀的方法。综述了微丝菌在培养分离、生理特性和影像识别以及调控等方面的研究进展,并对微丝菌的后续研究提出了建议和展望。     

Physicochemical Aspects of Activated Sludge in Relation to Stable Foam Formation

The presence of stable foams can seriously impair the ability of an activated sludge to produce a high-quality effluent. This paper examines how the physicochemical characteristics of the solids are related to foam formation and describes how the foaming potential of full-scale plants can be assessed. It also confirms that Microthrix parvicella can exhibit a variable morphology and shows that these variations are related to the physicochemical properties that characterize foam-forming solids.     

Lecane tenuiseta rotifers improves activated sludge settleability in laboratory scale SBR system at 13°C and 20°C

Two experiments at different temperatures were conducted in five laboratory‐scale bioreactors with enhanced nutrient removal simulating the work of sequencing batch reactors (SBRs). The process was operated in three 8‐hour cycles. The oxygen concentration, pH and temperature were controlled and maintained at 1 mg of O₂/L, 7 and 13°C, respectively, throughout the first two weeks and at 20°C for the next 10 days. The introduction of Lecane tenuiseta improved the settling properties of the activated sludge dominated by Microthrix parvicella at both temperatures tested. L. tenuiseta rotifers led to a reduction in filamentous bacteria abundance and did not negatively affect the chemical parameters of the effluent. For each temperature, there were no differences in COD, N_tot, N‐NH₄ or P‐PO₄ values between the treatment and control bioreactors. The results have shown that the application of L. tenuiseta is a promising biological tool for bulking prevention especially in a cold season.     

低温条件下低溶解氧污泥微膨胀的发生及分子生态学解析

采用SBR工艺处理实际生活污水,在低温条件下,通过降低溶解氧诱使活性污泥发生微膨胀,使污泥容积指数(SVI)维持在150~200 mL/g.研究了低温条件下活性污泥微膨胀的发生及活性污泥中微生物的生长,通过FISH技术对微膨胀状态下的优势丝状菌进行定性分析,确定低温下诱发低氧微膨胀的丝状菌是微丝菌(MPA223).与正常溶解氧时相比,微膨胀状态下COD和PO34-P-的去除率均上升,分别为80%和98%;NH4+-N和TN的去除率有所下降,分别为52%和28%;研究中还发现,低溶解氧导致了同步硝化反硝化(SND)现象的发生,约有15%的氮通过SND现象去除.     

Foam Formation, Anaerobiosis and Microthrix Parvicella

Microscopic examinations of the sludges associated with two incidents of foam formation in anaerobic digesters are described. In both cases, the dominant filamentous species was Microthrix parvicella. Preliminary growth studies with this species indicated that it could grow in both aerobic and anaerobic environments, but that in an anaerobic regime it did not produce polyphosphate granules. This suggests that M. parvicella may be involved in the luxury uptake of phosphate and, under strict anaerobic conditions, could compete with acetoclastic methanogens for acetate.     

寒冷地区城市污水处理厂污泥膨胀及其控制方法

分析了活性泥污系统发生污泥膨胀的主要原因及其中的丝状菌属,结合大庆乘风庄污水厂运行五年来两次膨胀的实际运行控制,提出了在寒冷地区活性污泥系统中,降低氧,低负荷外低温也是造成的原因之一,对此采用减小曝气池污染浓度或单池连续运动以提高负荷和供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。     

EXPERIENCE OF ACTIVATED-SLUDGE BULKING IN THE UK

The predominant filamentous bacteria which are found in bulking activated sludge in the UK have been assessed from a microscopic analysis of samples taken over a three-year period. There were major differences in the floc biology of samples received from plants treating predominantly domestic wastewaters and those of industrial origin. Most samples (84%) of domestic origin were dominated by two filament types: Microthrix parvicella was the dominant filament in 63% of the samples and Type 021N dominated in 21% of the samples. Nostocoida limicola and Sphaerotilus natans dominated in the remaining 16% of samples. The samples of industrial origin showed much greater filament diversity, with eight filament types routinely observed in high numbers. Type 021N was the most prevalent and M. parvicella was not observed in the industrial samples. Many domestic samples from sequencing batch reactors were dominated by M. parvicella. Based upon knowledge of the predominant filament type from microscopic examination. it was possible to identify the likely causes for their proliferation and suggest long-term solutions to achieve their eradication.     

Foaming in Activated-Sludge Processes: An Operator's Overview

The formation of stable surface foams, which is associated with characteristic filamentous microorganisms, is a worldwide phenomenon on activated-sludge plants. In excess, it can create operating difficulties and may cause a violation of effluent consent conditions due to high concentrations of suspended solids and solids-related biochemical oxygen demand. Despite its universal occurrence, the reasons for foaming are not clearly understood, and control measures tend to be non-specific, hit-or-miss strategies.
This paper presents an operator's perspective on (a) the current knowledge of foam-forming microorganisms, and (b) methods to control them.     

Extracellular polymers in activated sludge and stable foams

The hydrophobicity and surface polymer extracellular polymer characteristics of a range of foams and mixed liquor samples were examined and the species involved studied. The results show that, for samples dominated by Microthrix parvicella, the hydrophobicity of the solids was linearly related to the uronic acid content of the extracellular polymer polysaccharide. The stability of foams was increased significantly with the addition of polyvalent metal ions to the mixed liquors producing the foams.