scholarly journals Longevity Aspects of Potable Water Disinfected by Ionic Silver: Kinetic Experiments and Modeling

Water ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 258 ◽  
Author(s):  
Maria Petala ◽  
Vasilios Tsiridis ◽  
Efthymios Darakas ◽  
Margaritis Kostoglou
Keyword(s):  
Deposition Rate ◽  
Distribution Systems ◽  
Potable Water ◽  
Material Selection ◽  
Space Station ◽  
Water Storage ◽  
Bulk Water ◽  
Silver Concentration ◽  
Ti Alloy ◽  
Silver Deposition

In the International Space Station (ISS), Russian and European cosmonauts drink water disinfected by dissolved silver. For this to be effective, the concentration of silver should remain above a certain threshold from the moment of its initial disposition in storage tanks on earth until its final consumption in ISS. Unfortunately, during water tanks transportation to ISS and during storage in ISS, silver concentration has been reported to decrease intensively beyond any reason. This work examines the effect of different materials used in ISS water storage and distribution systems on the reduction of silver concentration. An experimental campaign has been organized where passivated stainless steel (SS), passivated and electropolished SS and titanium alloy coupons (official ISS grades) are exposed to simulated ISS potable water at different silver concentrations, different surface to volume ratios, and at stagnant or flow conditions. The evolution of silver concentration remaining in the bulk water is recorded with respect to the exposure time. A reaction engineering model for the Ag loss to the coupons is developed. The model is fitted to the experimental data in order to derive the reaction rate expression and the corresponding parameters. For passivated SS and electropolished SS the silver deposition rate depends on the initial silver concentration in water but is rather unaffected by the progress of silver deposition on the surface. On the other hand, for Ti alloy, while silver deposition rate still depends on initial silver concentration, it decreases continuously as silver deposition on the surface advances, implying that Ti alloy surface becomes gradually saturated and so prevents further silver deposition. Such a model can be useful for material selection and design of water storage and distribution facilities for ISS.

scholarly journals The impact of biofilms on water quality in long pipelines

2009 ◽  
Vol 30 (1) ◽  
pp. 16
Author(s):  
Jason Plumb ◽  
Geoffrey Puzon ◽  
Maneesha Ginige
Keyword(s):  
Water Quality ◽  
Distribution Systems ◽  
Water Distribution ◽  
Microbial Growth ◽  
Potable Water ◽  
Bulk Water ◽  
Human Consumption ◽  
Opportunistic Pathogens ◽  
The Impact

Limited water availability and increased water demand necessitates the use of long pipelines to distribute potable and non-potable water for human consumption or other purposes. The effects of microbial growth and activity on the quality of distributed water have been studied for many years, although in recent years much of this focus has shifted to understanding the effects of biofilms, rather than planktonic microorganisms, on water quality. Recently, it was estimated that 95% of all biomass in water distribution systems is in the form of pipewall biofilms, with only 5% of all biomass in the bulk water phase. Under favourable conditions, biofilms can impact water quality by increasing disinfectant demand, creating taste and odour problems, harbouring opportunistic pathogens and contributing to the potential for discoloured water events. More research is required to inform the development of guidelines for the management of biofilms in long pipelines to ensure the delivery of safe drinking water and to minimise impacts on water quality.

scholarly journals MUWS (Microbiology in Urban Water Systems) – an interdisciplinary approach to study microbial communities in urban water systems

2010 ◽  
Vol 3 (2) ◽  
pp. 91-99 ◽  
Author(s):  
P. Deines ◽  
R. Sekar ◽  
H. S. Jensen ◽  
S. Tait ◽  
J. B. Boxall ◽  
...  
Keyword(s):  
Microbial Ecology ◽  
Distribution Systems ◽  
Water Distribution ◽  
Potable Water ◽  
Water Distribution Systems ◽  
Water Systems ◽  
Urban Water ◽  
Infrastructure Systems ◽  
Urban Water Systems ◽  
Sewer Networks

Abstract. Microbiology in Urban Water Systems (MUWS) is an integrated project, which aims to characterize the microorganisms found in both potable water distribution systems and sewer networks. These large infrastructure systems have a major impact on our quality of life, and despite the importance of these systems as major components of the water cycle, little is known about their microbial ecology. Potable water distribution systems and sewer networks are both large, highly interconnected, dynamic, subject to time and varying inputs and demands, and difficult to control. Their performance also faces increasing loading due to increasing urbanization and longer-term environmental changes. Therefore, understanding the link between microbial ecology and any potential impacts on short or long-term engineering performance within urban water infrastructure systems is important. By combining the strengths and research expertise of civil-, biochemical engineers and molecular microbial ecologists, we ultimately aim to link microbial community abundance, diversity and function to physical and engineering variables so that novel insights into the performance and management of both water distribution systems and sewer networks can be explored. By presenting the details and principals behind the molecular microbiological techniques that we use, this paper demonstrates the potential of an integrated approach to better understand how urban water system function, and so meet future challenges.

Legionella and Public Water Supplies

1988 ◽  
Vol 20 (11-12) ◽  
pp. 5-10 ◽  
Author(s):  
J. S. Colbourne ◽  
P. J. Dennis ◽  
R. M. Trew ◽  
C. Berry ◽  
G. Vesey
Keyword(s):  
Surface Water ◽  
Heat Shock ◽  
Distribution Systems ◽  
Potable Water ◽  
Water Sources ◽  
Water Supplies ◽  
Indirect Immunofluorescent Assay ◽  
Water Mains ◽  
Legionnaires Disease ◽  
Indirect Immunofluorescent

A survey for legionella in public water supplies in England failed to detect culturable L.pneumophila in all but samples from taps in buildings; however, the organism was detected in underground and surface water sources and distribution systems using an indirect immunofluorescent assay (IFA) to L.pneumophila serogroup 1. Culturability was related to water temperatures above 20°C. In water mains L.pneumophila was associated with biofilms or sediment. Non-culturable L.pneumophila detected in potable waters by IFA were recovered by heat shock experiments demonstrating their viability. Although the strain found in potable water is rarely asociated with disease, monoclonal expression, a virulence marker, was altered by heat shock. These findings have implications for the prevention of legionellosis and may explain the sporadic nature of legionnaires disease in the community.

Multi-pathogen waterborne disease outbreak associated with a dinner cruise on Lake Michigan

2011 ◽  
Vol 140 (4) ◽  
pp. 621-625 ◽  
Author(s):  
F. SERDAREVIC ◽  
R. C. JONES ◽  
K. N. WEAVER ◽  
S. R. BLACK ◽  
K. A. RITGER ◽  
...  
Keyword(s):  
Distribution Systems ◽  
Heavy Rainfall ◽  
Potable Water ◽  
Lake Michigan ◽  
Disease Outbreak ◽  
Potential Risks ◽  
Stool Specimens ◽  
The One ◽  
Bodies Of Water ◽  
Water Holding

SUMMARYWe report an outbreak associated with a dinner cruise on Lake Michigan. This took place on the same day as heavy rainfall, which resulted in 42·4 billion liters of rainwater and storm runoff containing highly diluted sewage being released into the lake. Of 72 cruise participants, 41 (57%) reported gastroenteritis. Stool specimens were positive for Shigella sonnei (n=3), Giardia (n=3), and Cryptosporidium (n=2). Ice consumption was associated with illness (risk ratio 2·2, P=0·011). S. sonnei was isolated from a swab obtained from the one of the boat's ice bins. Environmental inspection revealed conditions and equipment that could have contributed to lake water contaminating the hose used to load potable water onto the boat. Knowledge of water holding and distribution systems on boats, and of potential risks associated with flooding and the release of diluted sewage into large bodies of water, is crucial for public health guidance regarding recreational cruises.

scholarly journals Legionella pneumophila and Protozoan Hosts: Implications for the Control of Hospital and Potable Water Systems

Pathogens ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 286 ◽  
Author(s):  
Muhammad Atif Nisar ◽  
Kirstin E. Ross ◽  
Melissa H. Brown ◽  
Richard Bentham ◽  
Harriet Whiley
Keyword(s):  
Legionella Pneumophila ◽  
Distribution Systems ◽  
Water Distribution ◽  
Potable Water ◽  
Water Systems ◽  
Water Disinfection ◽  
Health Concern ◽  
Waterborne Pathogen ◽  
Microbial Biofilms ◽  
Pontiac Fever

Legionella pneumophila is an opportunistic waterborne pathogen of public health concern. It is the causative agent of Legionnaires’ disease (LD) and Pontiac fever and is ubiquitous in manufactured water systems, where protozoan hosts and complex microbial communities provide protection from disinfection procedures. This review collates the literature describing interactions between L. pneumophila and protozoan hosts in hospital and municipal potable water distribution systems. The effectiveness of currently available water disinfection protocols to control L. pneumophila and its protozoan hosts is explored. The studies identified in this systematic literature review demonstrated the failure of common disinfection procedures to achieve long term elimination of L. pneumophila and protozoan hosts from potable water. It has been demonstrated that protozoan hosts facilitate the intracellular replication and packaging of viable L. pneumophila in infectious vesicles; whereas, cyst-forming protozoans provide protection from prolonged environmental stress. Disinfection procedures and protozoan hosts also facilitate biogenesis of viable but non-culturable (VBNC) L. pneumophila which have been shown to be highly resistant to many water disinfection protocols. In conclusion, a better understanding of L. pneumophila-protozoan interactions and the structure of complex microbial biofilms is required for the improved management of L. pneumophila and the prevention of LD.

Fungi from Potable Water: Interaction with Chlorine and Engineering Effects

1988 ◽  
Vol 20 (11-12) ◽  
pp. 153-159 ◽  
Author(s):  
William D. Rosenzweig ◽  
Wesley O. Pipes
Keyword(s):  
Water Samples ◽  
Distribution Systems ◽  
Water Distribution ◽  
Potable Water ◽  
Fungal Spores ◽  
Water Distribution Systems ◽  
Water Systems ◽  
Storage Tanks ◽  
Water Interaction ◽  
Low Concentrations

In recent years various types of imperfect fungi have been isolated from water systems. Fungal spores and mycelia can be inactivated by low concentrations of chlorine in the laboratory but survive in some habitats in water distribution systems. This report describes a field study which provides evidence that some types of fungi are able to grow in water distribution systems. Replicate samples from private residences were used to demonstrate that fungal densities are sometimes much greater than the levels which could be explained by adventitious spores. The microbiological content of water samples from fire hydrants was often significantly different from that of water samples from nearby private residences. The treated water input to distribution systems was found to be significantly lower in fungus content than water from private residences. Elevated storage tanks open to the atmosphere appear to be significant sources of fungal input to some systems.

DYNAMICS AND TOPOGRAPHY OF QUASI-2D NEEDLE-LIKE SILVER ELECTROCHEMICAL DEPOSITS UNDER A QUASI-STEADY-STATE REGIME

2009 ◽  
Vol 16 (05) ◽  
pp. 697-713
Author(s):  
M. A. PASQUALE ◽  
J. L. VICENTE ◽  
A. J. ARVIA
Keyword(s):  
Steady State ◽  
Mass Transport ◽  
Deposition Rate ◽  
Silver Ion ◽  
Stage Iii ◽  
Surface Relaxation ◽  
Scanning Electron Micrographs ◽  
Quasi Steady State ◽  
Silver Deposition ◽  
Needle Growth

The electrochemical formation of single silver needles from aqueous silver sulfate was studied under both potentiostatic and galvanostatic conditions utilizing different quasi-2D cells. Under potentiostatic conditions, four (I–IV) stages of growth were distinguished. Stage III involved single needle growth under a quasi-steady-state (q-ss) regime in which, at the millimeter scale, the tip profile remained almost unchanged. Fast growing needles exhibited a truncated quasi-conical tip, and slow growing ones approached prolate hemispheroids. At stage III, the almost constant q-ss silver deposition rate was evaluated from the tip front displacement (dL z /dt) perpendicularly to the tangential plane of the tip. For the cathode to anode potential difference in the range -1.00 ≤ E c-a ≤ -0.22 V , values of (dL z /dt) in the range 0.08–2.0 μm s-1 were obtained. At the needle stem, the q-ss radial silver deposition rate (dL x /dt) was about two orders of magnitude lower than (dL z /dt). The transition from stage III to IV was characterized by tip thickening, i.e. a change in the tip q-conical profile to that of a prolate hemispheroid, and eventual tip splitting. Scanning electron micrographs at the micrometer scale of single silver needle tips from potentiostatic runs showed either a defined crystallography or an irregular topography covered by a large number of tiny crystals. In contrast, stems were always faceted. This difference indicated that surface relaxation processes following silver ion mass transport and discharge played a relevant role in the needle growth mode. At stage III, the growth regime is described utilizing a dual diffusion (D) and migration (M) model consisting of a DM direct contribution that becomes dominant at the needle stem, and a space charge (SC)-assisted DM contribution that operates at the tip apex. This explanation is consistent with the local cathodic current density values, the concentration ratio of silver clusters at the stem and tip apex surface, and the distinct kinetic behavior of needles produced from potentiostatic and galvanostatic runs. The complex link between mass transport phenomena of silver ions from the binary solution side, the silver ion discharge at the interface and the surface relaxation of silver adatoms and clusters at the metal lattice shed new light on the aspects of single silver needle formation.

Damage to potable water reservoirs in the Darfield earthquake

2010 ◽  
Vol 43 (4) ◽  
pp. 429-431
Author(s):  
Robert A. Davey
Keyword(s):  
Distribution System ◽  
Potable Water ◽  
Water Storage ◽  
City Council ◽  
Water Reservoirs ◽  
Good Test ◽  
Damage Data

The Mw 7.1 earthquake that struck 40 km west of Christchurch on 4 September 2010 provided a good test of the robustness of the water storage and distribution system of one of our major cities to provide a secure supply of water. In this paper we present damage data from inspections of 54 reservoirs that were undertaken on behalf of Christchurch City Council and other owners. These included concrete, steel and timber tanks, five of which collapsed and four severely damaged.

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