Bacterial community structure in cooling water and biofilm in an industrial recirculating cooling water system

2013 ◽  
Vol 68 (4) ◽  
pp. 940-947 ◽  
Author(s):  
Jinmei Wang ◽  
Min Liu ◽  
Huijie Xiao ◽  
Wei Wu ◽  
Meijuan Xie ◽  
...  
Keyword(s):  
Community Structure ◽  
Bacterial Community ◽  
Water System ◽  
Cooling Water ◽  
Water Systems ◽  
Rrna Gene ◽  
Free Living ◽  
Cooling Water System ◽  
Attached Bacteria ◽  
Living Bacteria

Microbial fouling is a serious problem in open recirculating cooling water systems. The bacterial communities that cause it have not been fully understood. In this study, we analyzed the community structure of free-living bacteria and particle-attached bacteria in cooling water, and bacteria in biofilm collected from the wall of the water reservoir in an industrial recirculating cooling water system by construction of a 16S rRNA gene clone library. Based on amplified ribosomal DNA restriction analysis, clones of all three libraries were clustered into 45 operational taxonomic units (OTUs). Thirteen OTUs displaying 91–96% sequence similarity to a type strain might be novel bacterial species. Noted differences in community structure were observed among the three libraries. The relative species richness of the free-living bacteria in cooling water was much lower than that of particle-attached bacteria and bacteria in biofilm. The majority of the free-living bacterial community (99.0%) was Betaproteobacteria. The predominant bacteria in the particle-attached bacterial community were Alphaproteobacteria (20.5%), Betaproteobacteria (27.8%) and Planctomycetes (42.0%), while those in the biofilm bacterial community were Alphaproteobacteria (47.9%), Betaproteobacteria (11.7%), Acidobacteria (13.1%) and Gemmatimonadetes (11.3%). To control microbial fouling in industrial recirculating cooling water systems, additional physiological and ecological studies of these species will be essential.

scholarly journals Dynamics of Free-Living and Attached Bacterial Assemblages in Skeletonema sp. Diatom Cultures at Elevated Temperatures

2021 ◽  
Vol 8 ◽  
Author(s):  
Zichao Deng ◽  
Shouchang Chen ◽  
Ping Zhang ◽  
Xu Zhang ◽  
Jonathan M. Adams ◽  
...  
Keyword(s):  
Community Structure ◽  
Elevated Temperature ◽  
Bacterial Communities ◽  
Elevated Temperatures ◽  
Bacterial Species ◽  
Positive Interactions ◽  
Growth Stages ◽  
Free Living ◽  
Attached Bacteria ◽  
Living Bacteria

In the context of global warming, changes in phytoplankton-associated bacterial communities have the potential to change biogeochemical cycling and food webs in marine ecosystems. Skeletonema is a cosmopolitan diatom genus in coastal waters worldwide. Here, we grew a Skeletonema strain with its native bacterial assemblage at different temperatures and examined cell concentrations of Skeletonema sp. and free-living bacteria, dissolved organic carbon (DOC) concentrations of cultures, and the community structure of both free-living and attached bacteria at different culture stages. The results showed that elevated temperature increased the specific growth rates of both Skeletonema and free-living bacteria. Different growth stages had a more pronounced effect on community structure compared with temperatures and different physical states of bacteria. The effects of temperature on the structure of the free-living bacterial community were more pronounced compared with diatom-attached bacteria. Carbon metabolism genes and those for some specific amino acid pathways were found to be positively correlated with elevated temperature, which may have profound implications on the oceanic carbon cycle and the marine microbial loop. Network analysis revealed evidence of enhanced cooperation with an increase in positive interactions among different bacteria at elevated temperature. This may help the whole community to overcome the stress of elevated temperature. We speculate that different bacterial species may build more integrated networks with a modified functional profile of the whole community to cope with elevated temperature. This study contributes to an improved understanding of the response of diatom-associated bacterial communities to elevated temperature.

scholarly journals Heuristic Framework for Sustainable Cooling Water Systems Operations in Oil Facilities

2021 ◽  
Vol 15 ◽  
pp. 1-16
Author(s):  
Mustafa Hashim ◽  
Mimi Haryani Hassim ◽  
Denny KS Ng ◽  
Denny KS Ng
Keyword(s):  
High Efficiency ◽  
Cooling System ◽  
Water System ◽  
Cooling Water ◽  
Water Systems ◽  
Design Stage ◽  
Project Schedule ◽  
Residential Areas ◽  
Oil Companies ◽  
Cooling Water System

To meet the growing demand for cleaner environment from the society, most leading oil companies have committed to preserve environment via reduction of greenhouse gases, water and soil pollution as well as the use of natural resources. In most of the oil facilities, they required massive cooling systems to cool down process streams in order to meet the process requirements. The most common cooling system in oil facilities is evaporative cooling water system (ECWS) as such system has high efficiency. Cooling water is commonly used in offices and residential areas. However, the cooling water system is one of the utility systems that generates high environmental impacts due to high consumption of power, water and chemicals. Therefore, it is important to optimize the system in the early design stage of the project to operate in the most effective and efficient condition. In reality, many efforts may be missed out due to loose project definition, inexperience design engineer, hectic project schedule, or resource constraint. Therefore, in order to overcome the previous limitations, this paper presents a comprehensive heuristic improvement framework for cooling water systems in oil operating facilities.

scholarly journals ELIMINATION OF PSEUDOMONAS AERUGINOSA FROM WATER SYSTEMS: A REVIEW

2019 ◽  
Vol 8 (5) ◽  
Author(s):  
Kabirdas B. Ghorpade ◽  
Milind Suryawanshi ◽  
Sharda M. Shinde
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Natural Waters ◽  
Water System ◽  
Opportunistic Pathogen ◽  
Water Systems ◽  
Free Living ◽  
Gram Negative ◽  
Physical Conditions ◽  
Wide Range ◽  
Living Bacteria

Pseudomonads free-living bacteria that live primarily in soil, seawater, and fresh water. They also colonize plants and animals. Pseudomonads can grow in distilled water also. Pseudomonas spp., ubiquitous Gram negative bacilli, are found in natural waters such as lakes and rivers. On account of their tolerance to a wide variety of physical conditions and minimal nutrition requirements, Pseudomonas also can colonize biofilms in manmade systems such as drinking water. Pseudomonas aeruginosa is a major human opportunistic pathogen species of this group, which can cause a wide range of infections. In this review we have discussed effect of Bacteria on human health and the methods to control the Pseudomonas aeruginosa in water system. Keywords: Pseudomonas aeruginosa, Bacteriophages, water decontamination, Copper-silver ionization, Ozone, Pathogens.

Side stream biofiltration for improved biofouling control in cooling water systems

2000 ◽  
Vol 41 (4-5) ◽  
pp. 445-451 ◽  
Author(s):  
E.J. Daamen ◽  
J.W. Wouters ◽  
J.T.G. Savelkoul
Keyword(s):  
Nutrient Removal ◽  
Plug Flow ◽  
Water System ◽  
Cooling Water ◽  
Water Systems ◽  
Biofilm Growth ◽  
First Order ◽  
Side Stream ◽  
Cooling Water System ◽  
Kinetic Coefficients

Biological activity in open recirculating cooling water systems may lead to Microbial Induced Corrosion (MIC) and lower heat exchange efficiencies. The use of oxidizing biocides as a tool to control excessive biofilm formation in a cooling water system can be characterised as fighting the symptoms, because it does not take away the main cause of biofilm growth: the availability of nutrients. Due to frequent use of oxidizing biocides the microbial growth rate in the cooling water system studied (1–2 d−1) was even higher than the dilution rate (0.33 d−1). By means of an ASTRASAND®continuous sand filter used as a side stream biofilter it is possible to achieve considerable reductions in nutrients and in suspended biomass contents. The content of nutrients in the filter influent and effluent was expressed in terms of growth rates and was determined by batch experiments. Based on the assumptions of plug flow characteristics and first order reaction kinetics, the kinetic coefficients for nutrient removal were determined at k1=6 h−1 for fine (0.8–1.25 mm) and at k1=4.5 h−1 for coarse (1.4–2.0 mm) filter material. Due to the first order kinetics of nutrient removal and due to the improved filtration efficiencies at increasing influent biomass contents, it is concluded that a side stream biofilter introduces a self regulating process element in the cooling water system, leading to a faster recovery of the cooling water quality after upset conditions. Considerable savings in the use of oxidizing agents can be established.

scholarly journals Coupling of heterotrophic bacteria to phytoplankton bloom development at different <i>p</i>CO<sub>2</sub> levels: a mesocosm study

2008 ◽  
Vol 5 (4) ◽  
pp. 1007-1022 ◽  
Author(s):  
M. Allgaier ◽  
U. Riebesell ◽  
M. Vogt ◽  
R. Thyrhaug ◽  
H.-P. Grossart
Keyword(s):  
Community Structure ◽  
Heterotrophic Bacteria ◽  
Phytoplankton Bloom ◽  
C:N Ratio ◽  
Life Forms ◽  
Bacterial Activity ◽  
Free Living ◽  
Seawater Chemistry ◽  
Attached Bacteria ◽  
Living Bacteria

Abstract. The predicted rise in anthropogenic CO2 emissions will increase CO2 concentrations and decrease seawater pH in the upper ocean. Recent studies have revealed effects of pCO2 induced changes in seawater chemistry on a variety of marine life forms, in particular calcifying organisms. To test whether the predicted increase in pCO2 will directly or indirectly (via changes in phytoplankton dynamics) affect abundance, activities, and community composition of heterotrophic bacteria during phytoplankton bloom development, we have aerated mesocosms with CO2 to obtain triplicates with three different partial pressures of CO2 (pCO2): 350 μatm (1×CO2), 700 μatm (2×CO2) and 1050 μatm (3×CO2). The development of a phytoplankton bloom was initiated by the addition of nitrate and phosphate. In accordance to an elevated carbon to nitrogen drawdown at increasing pCO2, bacterial production (BPP) of free-living and attached bacteria as well as cell-specific BPP (csBPP) of attached bacteria were related to the C:N ratio of suspended matter. These relationships significantly differed among treatments. However, bacterial abundance and activities were not statistically different among treatments. Solely community structure of free-living bacteria changed with pCO2 whereas that of attached bacteria seemed to be independent of pCO2 but tightly coupled to phytoplankton bloom development. Our findings imply that changes in pCO2, although reflected by changes in community structure of free-living bacteria, do not directly affect bacterial activity. Furthermore, bacterial activity and dynamics of heterotrophic bacteria, especially of attached bacteria, were tightly correlated to phytoplankton development and, hence, may also potentially depend on changes in pCO2.

scholarly journals Physiological and Biochemical Characterization of Isolated Bacteria from a Coccolithophore Chrysotila dentata (Prymnesiophyceae) Culture

Diversity ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 2
Author(s):  
Xueru Wang ◽  
Yang Liu ◽  
Jun Sun
Keyword(s):  
Biochemical Characterization ◽  
Starch Hydrolysis ◽  
Dilution Method ◽  
Rrna Gene ◽  
Sequencing Analysis ◽  
Free Living ◽  
Attached Bacteria ◽  
Urease Test ◽  
Physiological And Biochemical ◽  
Living Bacteria

Coccolithophores are involved in oceanic carbon and nitrogen cycles, and they also have an impact on global climate change. Chrysotila dentata have a complex and close relationship with phycosphere bacteria. In this study, culturable phycosphere bacteria (free-living bacteria and attached bacteria) are isolated from C. dentata by a gradient dilution method and identified based on the 16S rRNA gene sequencing analysis. The phylogenetic tree (neighbor-joining tree, N-J tree) was constructed using the bacterial sequences and closest related sequences from GenBank. Colony characteristics, Gram nature, and physiological and biochemical characteristics were obtained based on a series of tests, such as the sugar utilization (glucose, arabinose, xylose, maltose, and mannitol) test, Voges–Proskauer reaction, urease tests, gelatin liquefaction, Gram test, starch hydrolysis, among others. In this study, seven strains (CF1, CF2, CF3, CF5, CF6, and CF7) of free-living bacteria (CF) and five strains (CA1, CA2, CA3, CA4, and CA5) of attached bacteria (CA) are isolated and identified. We found that the culturable phycosphere bacteria of C. dentata were mainly α-proteobacteria and γ-proteobacteria, with a small part of the CFB (Cytophaga-Flexibacter-Bacteroides) group bacteria and firmicutes. In this study, most α-proteobacteria can utilize malonate and positive in the urease test, meanwhile they can grow in a 7% NaCl medium. Differently to α-proteobacteria, γ-proteobacteria are more reactive, and can utilize maltose, glucose, arabinose, malonate, aesculin, and starch hydrolysis. Meanwhile, γ-proteobacteria can growth in a 7% NaCl and pH 5.7 medium, and some bacteria of this strain were positive in nitrate reduction. Firmicutes are similar to γ-proteobacteria: they are similar in reactivity, as they can utilize maltose, glucose, arabinose, malonate, aesculin, and starch hydrolysis, and can growth in a 7% NaCl and pH 5.7 medium. The difference is that some of firmicutes were positive in gelatin liquefaction and can utilize mannitol. The CFB group of bacteria were only positive in malonate, aesculin, and starch hydrolysis. The above results provide basic experimental data for further studies on the relationship between the coccolithophores and culturable phycosphere bacteria.

scholarly journals New Estimation of the Dosage of Scale Inhibitor in the Cooling Water System

2011 ◽  
Vol 8 (4) ◽  
pp. 1881-1885 ◽  
Author(s):  
Jiang Jiaomei ◽  
Xu Yanhua
Keyword(s):  
Ph Value ◽  
Water System ◽  
Cooling Water ◽  
Water Systems ◽  
Organic Phosphate ◽  
Scale Inhibitor ◽  
Cooling Water System ◽  
Metastable Zone ◽  
Verification Test ◽  
Critical Ph

In the cooling water system, excessive use of organic phosphate scale inhibitors is harmful to environment. Reducing the dosage of the organic phosphate scale inhibitor is important. A self-made jacketed crystallizer was used in this experiment. The critical pH values have been determined in cooling water systems with series of Ca2+concentrations by adding different concentration of the scale inhibitor ATMP (Amino Trimethylene Phosphonic Acid) according to the calcium carbonate Metastable zone theory. A model equation at 45 °C and pH=9 was proposed to estimate the lowest dose of the scale inhibitor ATMP. The measured pH value was approximate to the expected pH value in two cooling water systems through verification test.

Improving the Performance of Cooling Water Systems Using Exergy Analysis: A Novel Approach

2009 ◽  
Author(s):  
Mohammad Hassan Panjeshahi ◽  
Mona Gharaie ◽  
Lena Ahmadi
Keyword(s):  
Heat Exchanger ◽  
Exergy Analysis ◽  
Cooling Tower ◽  
Water System ◽  
Cooling Water ◽  
Water Systems ◽  
Exergy Destruction ◽  
Heat Exchanger Network ◽  
Cooling Water System ◽  
Circulating Cooling Water

Circulating cooling water systems almost serve all the operations of industrial plants where there is requirement of an external heat sink for heat removal and temperature control. Research on cooling systems focused on the energy analysis of individual components, cooling tower and heat exchanger network. However, the energy concept, alone is insufficient to describe the energy efficiency of the whole system. In this study, the exergy analysis is applied to evaluate the performance of the circulating cooling water system. To achieve this objective, the exergy destruction of the cooling tower and heat exchanger network in terms of different operational conditions are investigated. The results indicated that the exergy destruction in the cooling tower is increased by increasing the cooling tower inlet temperature; whereas the exergy destruction of the heat exchanger network decreases. Therefore, the problem of cooling water system for performance evaluation becomes an optimisation problem to search for the minimum exergetic destruction. Additionally, the second law efficiency of the cooling tower and water network is studied through the exergetic analysis.

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