太原市集中供热管网循环水中有害微生物的研究

调查了山西太原市集中供热循环水系统中主要造成管网腐蚀的有害微生物,包括粘液异养菌,硫酸盐还原菌,铁细菌,真菌,测定了各菌群的数量分布,类型及与水温之间的关系。结果表明：在管网供热期间,循环水中有害菌菌数普遍低于管网腐蚀的菌数指标;停止供热期间,循环水中菌数超标,对管网赞成一定的腐蚀。     

太原市集中供热管网循环水中有害微生物的研究*

调查了山西太原市集中供热循环水系统中主要造成管网腐蚀的有害微生物，包括粘液异养菌、 硫酸盐还原菌、铁细菌、真菌；测定了各菌群的数量分布、类型及与水温之间的关系。结果表明：在管 网供热期间，循环水中有害菌菌数普遍低于管网腐蚀的菌数指标；停止供热期间，循环水中菌数超 标，对管网造成一定的腐蚀。     

异噻唑酮用作循环冷却水杀菌灭藻剂的研究

本试验采用杯碟法、试管稀释法和显微直接计数法测试异噻唑酮对常见菌藻的抑杀效果,并用该药剂对循环冷却水主要危害菌——硫酸盐还原菌,铁细菌和形成粘液的异养菌进行室内静态杀菌试验。结果表明,其杀菌灭藻效果优于目前常用的工业杀菌剂,投药量10ppm,对水中主要危害菌的杀灭率达到99%以上。     

应用季铵盐控制炼油厂循环水中菌藻危害的研究

在调查东方红炼油厂循环冷却水系统被腐蚀危害的基础上,针对主要危害微生物——铁细菌、硫酸盐还原菌和形成粘液的异养菌,从4 7种药剂中筛选出既能杀菌灭藻,又具有污垢剥离作用的高效低毒药剂季铵盐——十二烷基二甲基苄基氯化铵(muc)。经小试中试及采用高低剂量结合、间隔冲击式瞬间投加方法进行的生产性试验,表明其杀菌率达99％;污垢抑制率95％以上,冷却塔壁菌藻抑制率达99％;挂片腐蚀率1．6密耳／年。     

循环水中影响十二烷基二甲基苄基氯化铵杀菌作用的因素

季胺盐在医学上作为清洁消毒剂早巳为人们所熟知,曾密切结合致病菌类做了影响其消毒杀菌效果因素的研究。然而关于工业循环冷却水系统中应用于控制腐蚀危害微生物有关影响因素,却很少见到报道。为了控制工业循环水中微生物造成的腐蚀危害,我们针对从循环水中分离的主要腐蚀危害菌——硫酸盐还原菌、铁细菌及形成粘液的异养菌,筛选到了高     

北京热电厂除盐水系统中有害微生物的调查

本文报道了除盐水系统中有害菌的分布,菌量随时间变化的调查结果。确定了北京热电厂微生物导致的危害主要是由于水源有机物污染严重,进入除盐系统后得不到彻底清除,给菌类提供了营养源;另外高pH值也影响了加氯杀菌效果,形成了以粘液异养菌和真菌为优势菌的菌膜,污堵设备,影响生产。从11月到次年4月枯水季节,菌繁殖更加严重。菌膜是以镰孢霉、茎点霉等霉菌为“骨架”,以假单孢菌、微球菌等细菌及其大量多糖分泌物为“实体”的聚合物。从菌膜和水体中共鉴定了5属7个种的细菌,6麒10个种的真菌,l株普通脱硫弧菌及几株铁细菌。     

二氧化氯杀灭除盐水系统中有害菌的研究

本文报道了杀菌剂二氧化氯对热电厂除盐水系统中有害菌的杀灭作用,并与氯的杀菌率作了比较。利用二氧化氯进行杀菌时,对粘液异养菌使用2ppm;铁细菌、硫酸盐还原菌使用1ppm;真菌使用2ppm,杀菌率达90—99％;而使用氯达到同样杀菌率需4—5 ppm。杀灭天然菌膜中细菌、真苗则需比人工混合菌提高三分之一以上的投药量。在5—60 min的接触时间内杀菌率提高5％,低剂量下随环境pH值(6一11)和温度(10—50℃)的上升,杀菌率有所提高。除50ppm以上的蛋白胨外,所试的糖、酸、氨均不影响二氧化氯的杀菌活性,但明显降低氯的杀菌作用。二氧化氯杀菌中出现失话余量,它同初始投量相比,杀菌率最高可差20—30％。     

微生物对油田污水-聚丙烯酰胺体系粘度的影响

比较了厌氧和曝气处理后的油田采出水配制聚丙烯酰胺溶液(采出水-聚丙烯酰胺体系)粘度及该体系中腐生菌,铁细菌和硫酸盐还原菌的数量变化。结果表明,曝气有利于聚合物溶液粘度的保持,粘度损失率明显低于厌氧采出水-聚合物体系。总体上,腐生菌或其代谢产物对聚合物粘度的影响很小;铁细菌可以利用聚合物生长,是破坏聚合物粘度的主要微生物类群;硫酸盐还原菌不能直接利用大分子量聚合物,可以利用小分子或分子链断裂的聚合物生长。     

硫酸盐还原菌对杀菌灭藻剂的抗药性研究进展

随着电厂循环冷却水系统中杀菌灭藻剂的长期及不科学使用,细菌对杀菌灭藻剂的抗药性问题日益严峻。研究循环冷却水系统中相关细菌的抗药性具有一定的理论价值及实用价值。本文综述了近年来有关硫酸盐还原菌对各类杀菌灭藻剂的抗药性及其抗药性机制的研究进展,内容主要涉及细菌对杀菌灭藻剂的抗性概念、国内外细菌的抗药现状、杀菌灭藻剂的杀菌机制和细菌的抗药机制等。     

炼油厂冷却器管道生物垢中铁细菌、硫细菌及硫酸盐还原菌的分离和鉴定

炼油厂污水经活性污泥处理及砂滤后,在冷却水系统中循环使用,冷却器管壁上有深棕色软垢形成。从垢中分离到11株铁细菌,经鉴定其中5株为锈色纤毛菌(Leplothrix ochracea);3株为浮游球衣细菌(Sphaerotilus natans);1株为大单鞘铁细菌(Sideromonas major);2株为有鞘丝状铁细菌,按其所具氧化铁及氧化锰的能力属于纤毛菌属,但其培养及形态特征与该属中已知种比较有较显著的差别。     

Microbial fouling community analysis of the cooling water system of a nuclear test reactor with emphasis on sulphate reducing bacteria

Culture and molecular-based techniques were used to characterize bacterial diversity in the cooling water system of a fast breeder test reactor (FBTR). Techniques were selected for special emphasis on sulphate-reducing bacteria (SRB). Water samples from different locations of the FBTR cooling water system, in addition to biofilm scrapings from carbon steel coupons and a control SRB sample were characterized. Whole genome extraction of the water samples and SRB diversity by group specific primers were analysed using nested PCR and denaturing gradient gel electrophoresis (DGGE). The results of the bacterial assay in the cooling water showed that the total culturable bacteria (TCB) ranged from 10(3) to 10(5)?cfu?ml(-1); iron-reducing bacteria, 10(3) to 10(5)?cfu?ml(-1); iron oxidizing bacteria, 10(2) to 10(3)?cfu?ml(-1) and SRB, 2-29?cfu?ml(-1). However, the counts of the various bacterial types in the biofilm sample were 2-3 orders of magnitude higher. SRB diversity by the nested PCR-DGGE approach showed the presence of groups 1, 5 and 6 in the FBTR cooling water system; however, groups 2, 3 and 4 were not detected. The study demonstrated that the PCR protocol influenced the results of the diversity analysis. The paper further discusses the microbiota of the cooling water system and its relevance in biofouling.     

Factors Stimulating Propagation of Legionellae in Cooling Tower Water

Our survey of cooling tower water demonstrated that the highest density of legionellae, ≥10⁴ CFU/100 ml, appeared in water containing protozoa, ≥10² MPN/100 ml, and heterotrophic bacteria, ≥10⁶ CFU/100 ml, at water temperatures between 25 and 35°C. Viable counts of legionellae were detected even in the winter samples, and propagation, up to 10⁵ CFU/100 ml, occurs in summer. The counts of legionellae correlated positively with increases in water temperature, pH, and protozoan counts, but not with heterotrophic bacterial counts. The water temperature of cooling towers may promote increases in the viable counts of legionellae, and certain microbes, e.g., protozoa or some heterotrophic bacteria, may be a factor stimulating the propagation of legionellae.     

Ecological studies of Legionella species. I. Viable counts of Legionella pneumophila in cooling tower water

The occurrence and viable counts of Legionella pneumophila in acid-treated water samples of 62 cooling towers on the main island of Japan were determined by inoculating them onto plates of Wadowsky-Yee-Okuda (WYO) agar medium. WYO plate cultures of 39 (63%) of the samples yielded L. pneumophila with viable counts ranging from 10 to 10(4) colony-forming units per 100 ml. Of the L. pneumophila isolates, 157 were serologically identified as serogroup 1, and the remaining 21 were agglutinated by serogroup 3 (2 strains) and serogroup 6 (19 strains) antisera. In each culture-positive water sample, the pH and the number of other bacteria were found not be statistically significantly correlated with the viable counts of L. pneumophila. However, a higher rate of recovery of L. pneumophila was obtained with the water samples with a smaller number of other bacteria. Practical use of commercially available antialgal or antimicrobial agents was found not to be significantly effective for controlling the occurrence and growth of L. pneumophila in cooling tower water.     

Biofouling and microbial corrosion problem in the thermo-fluid heat exchanger and cooling water system of a nuclear test reactor

This article discusses aspects of biofouling and corrosion in the thermo-fluid heat exchanger (TFHX) and in the cooling water system of a nuclear test reactor. During inspection, it was observed that >90% of the TFHX tube bundle was clogged with thick fouling deposits. Both X-ray diffraction and Mössbauer analyses of the fouling deposit demonstrated iron corrosion products. The exterior of the tubercle showed the presence of a calcium and magnesium carbonate mixture along with iron oxides. Raman spectroscopy analysis confirmed the presence of calcium carbonate scale in the calcite phase. The interior of the tubercle contained significant iron sulphide, magnetite and iron-oxy-hydroxide. A microbiological assay showed a considerable population of iron oxidizing bacteria and sulphate reducing bacteria (10⁵ to 10⁶ cfu g^?1 of deposit). As the temperature of the TFHX is in the range of 45–50°C, the microbiota isolated/assayed from the fouling deposit are designated as thermo-tolerant bacteria. The mean corrosion rate of the CS coupons exposed online was ～2.0 mpy and the microbial counts of various corrosion causing bacteria were in the range 10³ to 10⁵ cfu ml^?1 in the cooling water and 10⁶ to 10⁸ cfu ml^?1 in the biofilm.     

Isolation of Klebsielleae from within living wood.

Previous studies from this laboratory have documented the presence of coliform bacteria emanating from wooden reservoirs containing finished drinking water. Coliforms were identified as Klebsiella pneumoniae and Enterobacter spp. In the present report, evidence is presented which suggests that the origin of these coliforms is from the wood used to construct the reservoirs. In liquid expressed from freshly cut redwood, total bacterial counts in the range of 10(5) to 10(6)/ml were commonly observed. When present, coliform counts were over 10(3)/ml of expressed liquid. E. agglomerans was the most prevalent coliform present, but Klebsiella was isolated from freshly cut logs. Citrobacter freundii was also occasionally isolated. No fecal coliform-positive Klebsiella were obtained from any of the samples. Highest total bacteria and coliform counts were observed in sapwood specimens. Coliforms were present throughout sapwood as evidenced by contact plating serial sections of freshly cut wood. Scanning electron micrographs illustrate the presence of bacterial colonies within sapwood tracheids. Other wood species also contained coliform bacteria but in numbers lower than found in redwood.     

Isolation of Klebsielleae from within living wood.

Previous studies from this laboratory have documented the presence of coliform bacteria emanating from wooden reservoirs containing finished drinking water. Coliforms were identified as Klebsiella pneumoniae and Enterobacter spp. In the present report, evidence is presented which suggests that the origin of these coliforms is from the wood used to construct the reservoirs. In liquid expressed from freshly cut redwood, total bacterial counts in the range of 10(5) to 10(6)/ml were commonly observed. When present, coliform counts were over 10(3)/ml of expressed liquid. E. agglomerans was the most prevalent coliform present, but Klebsiella was isolated from freshly cut logs. Citrobacter freundii was also occasionally isolated. No fecal coliform-positive Klebsiella were obtained from any of the samples. Highest total bacteria and coliform counts were observed in sapwood specimens. Coliforms were present throughout sapwood as evidenced by contact plating serial sections of freshly cut wood. Scanning electron micrographs illustrate the presence of bacterial colonies within sapwood tracheids. Other wood species also contained coliform bacteria but in numbers lower than found in redwood.     

Microbial fouling community analysis of the cooling water system of a nuclear test reactor with emphasis on sulphate reducing bacteria

Culture and molecular-based techniques were used to characterize bacterial diversity in the cooling water system of a fast breeder test reactor (FBTR). Techniques were selected for special emphasis on sulphate-reducing bacteria (SRB). Water samples from different locations of the FBTR cooling water system, in addition to biofilm scrapings from carbon steel coupons and a control SRB sample were characterized. Whole genome extraction of the water samples and SRB diversity by group specific primers were analysed using nested PCR and denaturing gradient gel electrophoresis (DGGE). The results of the bacterial assay in the cooling water showed that the total culturable bacteria (TCB) ranged from 10³ to 10⁵ cfu ml^?1; iron-reducing bacteria, 10³ to 10⁵ cfu ml^?1; iron oxidizing bacteria, 10² to 10³ cfu ml^?1 and SRB, 2–29 cfu ml^?1. However, the counts of the various bacterial types in the biofilm sample were 2–3 orders of magnitude higher. SRB diversity by the nested PCR-DGGE approach showed the presence of groups 1, 5 and 6 in the FBTR cooling water system; however, groups 2, 3 and 4 were not detected. The study demonstrated that the PCR protocol influenced the results of the diversity analysis. The paper further discusses the microbiota of the cooling water system and its relevance in biofouling.     

Microbiology of Anaerobic Sludge Fermentation: I. Enumeration of the Nonmethanogenic Anaerobic Bacteria1

An anaerobic medium containing sludge supernatant fluid and glucose was used for enumeration of bacteria from the sludge fermentation. Comparison of viable counts from several separate samples consistently showed 10 to 100 times more anaerobic than aerobic bacteria. However, viable counts of the various samples differed by as much as 10 times; this variation probably reflects a change in the natural environment or sampling errors, or a combination of the two. Direct microscopic counts yielded values of about 10(10)/ml. The discrepancy between viable (10(8) to 10(9)/ml) and direct counts may be due to large numbers of dead cells. Random isolates of representative colonies from high dilutions exhibited the ability to ferment sugars and are not likely to be methane bacteria.     

Electron acceptors for anaerobic oxidation of methane drive microbial community structure and diversity in mud volcanoes

Mud volcanoes (MVs) emit globally significant quantities of methane into the atmosphere, however, methane cycling in such environments is not yet fully understood, as the roles of microbes and their associated biogeochemical processes have been largely overlooked. Here, we used data from high‐throughput sequencing of microbial 16S rRNA gene amplicons from six MVs in the Junggar Basin in northwest China to quantify patterns of diversity and characterize the community structure of archaea and bacteria. We found anaerobic methanotrophs and diverse sulfate‐ and iron‐reducing microbes in all of the samples, and the diversity of both archaeal and bacterial communities was strongly linked to the concentrations of sulfate, iron and nitrate, which could act as electron acceptors in anaerobic oxidation of methane (AOM). The impacts of sulfate/iron/nitrate on AOM in the MVs were verified by microcosm experiments. Further, two representative MVs were selected to explore the microbial interactions based on phylogenetic molecular ecological networks. The sites showed distinct network structures, key species and microbial interactions, with more complex and numerous linkages between methane‐cycling microbes and their partners being observed in the iron/sulfate‐rich MV. These findings suggest that electron acceptors are important factors driving the structure of microbial communities in these methane‐rich environments.