Relationship between the morphology of bacteriophages and their persistence in the environment

1997 ◽  
Vol 35 (11-12) ◽  
pp. 129-132 ◽  
Author(s):  
J. Lasobras ◽  
M. Muniesa ◽  
J. Frías ◽  
F. Lucena ◽  
J. Jofre
Keyword(s):  
Water Treatment ◽  
Bacteroides Fragilis ◽  
Coli Strain ◽  
Somatic Coliphages ◽  
E Coli ◽  
Treatment Processes ◽  
Morphological Differences ◽  
Myoviridae Family ◽  
Siphoviridae Family

The aim of the present work was to observe the morphological differences between bacteriophages from sewage, recent pollution and those from samples that contain microorganisms that have survived either natural inactivation or water treatment processes (persistent pollution). We studied the occurrence of bacteriophages infecting Bacteroides fragilis (HSP40 strain), F-specific coliphages (HS(pFamp)R strain) and somatic coliphages (CN13 strain). Phages isolated with B. fragilis in both wastewater and samples with persistent pollution were in all cases members of the Siphoviridae group with flexible tails. With E. coli strain HS(pFamp)R we detected F-specific coliphages in 97.7% wastewater. However, the percentage decreased to 76.9% in samples with persistent pollution. In the case of somatic coliphages in wastewater, detected using E. coli CN13, 91% of the phages belonged to the Myoviridae family and a 6% to the Siphoviridae family. In contrast, in persistent pollution samples, an increase of Siphoviridae phages was observed (up to 26.4%).

Bacteriophage removal in water treatment plants

1995 ◽  
Vol 31 (5-6) ◽  
pp. 69-73 ◽  
Author(s):  
J. Jofre ◽  
E. Ollé ◽  
F. Lucena ◽  
F. Ribas
Keyword(s):  
Water Treatment ◽  
Distribution Network ◽  
Bacteroides Fragilis ◽  
The Other ◽  
Model Organisms ◽  
Raw Water ◽  
Somatic Coliphages ◽  
Treatment Processes ◽  
Water Treatment Plants ◽  
Human Enteric Viruses

Presence of bacteriophages was evaluated at different stages of two water treatment plants in order to investigate the usefulness of phages as model organisms for assessing the efficiency of the processes. Bacteriophages tested were somatic coliphages, F-specific coliphages and phages infecting Bacteroides fragilis. The presence of human enteric viruses was determined as well in the raw water, the finished water and in samples taken in the distribution network. Results show that in these particular treatment plants, which include prechlorination, phages infecting B. fragilis are more resistant to the treatment processes than the other two phages studied.

scholarly journals Complete Genome Sequence of Escherichia coli Strain WG5

2018 ◽  
Vol 6 (2) ◽  
Author(s):  
Lejla Imamovic ◽  
Maria-Anna Misiakou ◽  
Eric van der Helm ◽  
Gianni Panagiotou ◽  
Maite Muniesa ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Genome Sequence ◽  
Complete Genome Sequence ◽  
Complete Genome ◽  
Coli Strain ◽  
Somatic Coliphages ◽  
E Coli

ABSTRACT Escherichia coli strain WG5 is a widely used host for phage detection, including somatic coliphages employed as standard ISO method 10705-1 (2000). Here, we present the complete genome sequence of a commercial E. coli WG5 strain.

Illite for the removal of E. coli by filtration in water treatment processes: a comparative study

2019 ◽  
Vol 163 ◽  
pp. 270-280
Author(s):  
Mun-Ju Kim ◽  
Chang-Gu Lee ◽  
Chang-Hee Lee ◽  
Seong-Jik Park
Keyword(s):  
Water Treatment ◽  
Comparative Study ◽  
E Coli ◽  
Treatment Processes

Water Treatment Considerations–Aquatic Humus

1983 ◽  
Vol 15 (S2) ◽  
pp. 95-101 ◽  
Author(s):  
E T Gjessing
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Humic Substances ◽  
Health Effects ◽  
Surface Waters ◽  
Cold Climate ◽  
Treatment Processes ◽  
Aquatic Humus ◽  
Treatment Considerations

For several reasons the surface waters in cold climate areas are coloured due to humic substances. There are two major objections against humus in drinking water, the first is concerned with aesthetical and practical problems and the second is due to indirect negative health effects. There are essentially three different methods in use today for the removal or reduction of humus colour in water: (1) Addition of chemicals with the intention of reducing the “solubility”, (2) Addition of chemicals in order to bleach or mineralize the humus, and (3) Filtration with the intention of removal of coloured particles and some of the “soluble” colour. The treatment processes are discussed.

Practical Guide to Determine the Impact of Radon and Other Radionuclides on Water Treatment Processes

1992 ◽  
Vol 26 (5-6) ◽  
pp. 1255-1264
Author(s):  
K. L. Martins
Keyword(s):  
Activated Carbon ◽  
Water Treatment ◽  
Environmental Protection Agency ◽  
Treatment Plant ◽  
Water Treatment Plant ◽  
Packed Tower ◽  
Treatment Processes ◽  
Radioactivity Exposure ◽  
The Impact ◽  
Percent Removal

During treatment of groundwater, radon is often coincidentally removed by processes typically used to remove volatile organic compounds (VOCs)-for example, processes such as liquid-phase granular activated carbon (LGAC) adsorption and air stripping with vapor-phase carbon (VGAC). The removal of radon from drinking water is a positive benefit for the water user; however, the accumulation of radon on activated carbon may cause radiologic hazards for the water treatment plant operators and the spent carbon may be considered a low-level radioactive waste. To date, most literature on radon removal by water treatment processes was based on bench- or residential-scale systems. This paper addresses the impact of radon on municipal and industrial-scale applications. Available data have been used todevelop graphical methods of estimating the radioactivity exposure rates to facility operators and determine the fate of spent carbon. This paper will allow the reader to determine the potential for impact of radon on the system design and operation as follows.Estimate the percent removal of radon from water by LGAC adsorbers and packed tower air strippers. Also, a method to estimate the percent removal of radon by VGAC used for air stripper off-gas will be provided.Estimate if your local radon levels are such that the safety guidelines, suggested by USEPA (United States Environmental Protection Agency), of 25 mR/yr (0.1 mR/day) for radioactivity exposure may or may not be exceeded.Estimate the disposal requirements of the waste carbon for LGAC systems and VGAC for air stripper “Off-Gas” systems. Options for dealing with high radon levels are presented.

Transport of escherichia coli through soil to groundwater traced by randomly amplified polymorphic DNA (RAPD)

1997 ◽  
Vol 35 (11-12) ◽  
pp. 351-357 ◽  
Author(s):  
R. Rothmaier ◽  
A. Weidenmann ◽  
K. Botzenhart
Keyword(s):  
Negative Impact ◽  
Random Amplified Polymorphic Dna ◽  
Coli Strain ◽  
Soil Samples ◽  
Test Field ◽  
Liquid Manure ◽  
E Coli ◽  
Rapd Pattern ◽  
Geological Situation ◽  
Different Strains

Isolates (50) of E. coli obtained from liquid manure (20 bovine, 20 porcine) were genotyped using random amplified polymorphic DNA (RAPD). Typing revealed 9 and 14 different strains in bovine and porcine liquid manure respectively with no strains in common. One porcine strain, showing a simple RAPD pattern, was subcultured and spread on a test field (1.5l/m2 at 1010 cfu/l) in a drinking water protection zone with loamy to sandy sediments in the Donauried area, Baden-Wurttemberg. Soil samples and groundwaters were collected at monthly intervals October 1994 – June 1995 during which 114 E. coli isolates were recovered. The first occurrence and maximum concentration of E. coli in soil samples taken from more than 20cm depth was in January 1995, declining rapidly with depth and time. All isolates from soil and only one from groundwater showed the RAPD pattern of the spread E. coli strain. The results could not demonstrate a severe negative impact of the spreading of liquid manure on the bacteriological quality of the groundwater in the given geological situation. The distinct strain patterns found in different kinds of liquid manure suggest that genotyping of E. coli by RAPD may be an adequate tool for tracing sources of faecal contamination.

Removal of sulphite-reducing clostridia spores by full-scale water treatment processes as a surrogate for protozoan (oo)cysts removal

2000 ◽  
Vol 41 (7) ◽  
pp. 165-171 ◽  
Author(s):  
W. A. Hijnen ◽  
J. Willemsen-Zwaagstra ◽  
P. Hiemstra ◽  
G. J. Medema ◽  
D. van der Kooij
Keyword(s):  
Water Treatment ◽  
Removal Efficiency ◽  
Water Quality Monitoring ◽  
Full Scale ◽  
Process Conditions ◽  
Safe Drinking Water ◽  
Unit Process ◽  
Treatment Processes ◽  
Scale Unit ◽  
Micro Organisms

At eight full-scale water treatment plants in the Netherlands the removal of spores of sulphite-reducing clostridia (SSRC) was determined. By sampling and processing large volumes of water (1 up to 500 litres) SSRC were detected after each stage of the treatment. This enabled the assessment of the removal efficiency of the full-scale unit processes for persistent micro-organisms. A comparison with literature data on the removal of Cryptosporidium and Giardia by the same type of processes revealed that SSRC can be considered as a potential surrogate. The average Decimal Elimination Capacity (DEC) of the overall treatment plants ranged from 1.3–4.3 log. The observed actual log removal of SSRC by the unit processes and the overall treatment at one of the studied locations showed that the level of variation in removal efficiency was approximately 2 log. Moreover, from the actual log removal values it was observed that a low SSRC removal by one unit process is partly compensated by a higher removal by subsequent unit processes at this location. SSRC can be used for identification of the process conditions that cause variation in micro-organism removal which may lead to process optimization. Further research is necessary to determine the optimal use of SSRC in water quality monitoring for the production of microbiologically safe drinking water.

Antibacterial silver-diatomite nanocomposite ceramic with low silver release

2019 ◽  
Vol 20 (2) ◽  
pp. 633-643
Author(s):  
Xiaopeng Qi ◽  
Junwei Chen ◽  
Qian Li ◽  
Hui Yang ◽  
Honghui Jiang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Water Treatment ◽  
Photoelectron Spectroscopy ◽  
Bactericidal Effect ◽  
Ceramic Filter ◽  
Ceramic Filters ◽  
X Ray ◽  
E Coli ◽  
Point Of Use ◽  
Silver Release

Abstract There is an urgent need for an effective and long-lasting ceramic filter for point-of-use water treatment. In this study, silver-diatomite nanocomposite ceramic filters were developed by an easy and effective method. The ceramic filters have a three-dimensional interconnected pore structure and porosity of 50.85%. Characterizations of the silver-diatomite nanocomposite ceramic filters were performed using scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. Silver nanoparticles were confirmed to be formed in situ in the ceramic filter. The highest silver concentration in water was 0.24 μg/L and 2.1 μg/L in short- and long-term experiments, indicating very low silver-release properties of silver-diatomite nanocomposite ceramic filter. The nanocomposite ceramics show strong bactericidal activity. When contact time with Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) of 105 colony forming units (CFU)/mL exceeded 3 h, the bactericidal rates of the four different silver content ceramics against E. coli and S. aureus were all 100%. Strong bactericidal effect against E. coli with initial concentration of 109 CFU/mL were also observed in ceramic newly obtained and ceramic immersed in water for 270 days, demonstrating its high stability. The silver-diatomite nanocomposite ceramic filters could be a promising candidate for point-of-use water treatment.

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