scholarly journals Detection, integration and persistence of aeromonads in water distribution pipe biofilms

2004 ◽  
Vol 2 (2) ◽  
pp. 83-96 ◽  
Author(s):  
A.-M. Bomo ◽  
M. V. Storey ◽  
N. J. Ashbolt
Keyword(s):  
Human Health ◽  
Water Distribution ◽  
Water System ◽  
Water Systems ◽  
Biofilm Reactor ◽  
Recycled Water ◽  
Decay Kinetics ◽  
Aeromonas Caviae ◽  
Health Significance

The occurrence of Aeromonas spp. within biofilms formed on stainless steel (SS), unplasticized polyvinyl chloride (uPVC) and glass (GL) substrata was investigated in modified Robbins Devices (MRD) in potable (MRD-p) and recycled (MRD-r) water systems, a Biofilm Reactor™ (BR) and a laboratory-scale pipe loop (PL) receiving simulated recycled wastewater. No aeromonads were isolated from the MRD-p whereas 3–10% of SS and uPVC coupons (mean 3.85 CFU cm−2 and 12.8 CFU cm−2, respectively) were aeromonad-positive in the MRD-r. Aeromonads were isolated from six SS coupons (67%) (mean 63.4 CFU cm−2) and nine uPVC coupons (100%) (mean 6.50×102 CFU cm−2) in the BR™ fed with recycled water and from all coupons (100%) in the simulated recycled water system (PL). Mean numbers of aeromonads on GL and SS coupons were 5.83×102 CFU cm−2 and 8.73×102 CFU cm−2, respectively. No isolate was of known human health significance (i.e. Aeromonas caviae, A. hydrophila or A. veronii), though they were confirmed as Aeromonas spp. by PCR and fluorescence in situ hybridization (FISH). Challenging the PL biofilms with a slug dose of A. hydrophila (ATCC 14715) showed that biofilm in the PL accumulated in the order of 103–104A. hydrophila cm−2, the number of which decreased over time, though could not be explained in terms of conventional 1st order decay kinetics. A sub-population of FISH-positive A. hydrophila became established within the biofilm, thereby demonstrating their ability to incorporate and persist in biofilms formed within distribution pipe systems. A similar observation was not made for culturable aeromonads, though the exact human health significance of this remains unknown. These findings, however, further question the adequacy of culture-based techniques and their often anomalous discrepancy with direct techniques for the enumeration of bacterial pathogens in environmental samples.

scholarly journals New Challenges in Water Systems

Water ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2340 ◽  
Author(s):  
Helena M. Ramos ◽  
Armando Carravetta ◽  
Aonghus Mc Nabola
Keyword(s):  
Water Distribution ◽  
Risk Function ◽  
Water System ◽  
Distribution Networks ◽  
Water Systems ◽  
Operating Conditions ◽  
Integrated Analysis ◽  
System Efficiency ◽  
Pressurized Water ◽  
New Challenges

New challenges in water systems include different approaches from analysis of failures and risk assessment to system efficiency improvements and new innovative designs. In water distribution networks (WDNs), the risk function is a measure of its vulnerability level and security loss. Analyses of transient flows which are associated with the most dangerous operating conditions, are compulsory to grant the system liability both in water quantity, quality, and management. Specific equipment, such as air valves are used in pressurized water pipes to manage the air inside associated with the filling process, that can also act as a control mechanism, where the major limitation is its reliability. Advanced tools are developed specifically to smart water grids implementation and operation. The water system efficiency and water-energy nexus, through the implementation of suitable, pressure control and energy recovery devices, and pumped-storage hydropower solutions, provide guidelines for the determination of the most technical cost-effective result. Integrated analysis of water and energy allows more reliable, flexible, and sustainable eco-design projects, reaching better resilience systems through new concepts. The development of model simulations, based on hydraulic simulators and computational fluid dynamics (CFD), conjugating with field or experimental tests, supported by advanced smart equipment, allow the control, identification, and anticipation of complex events necessary to maintain the water system security and efficiency.

Rainwater Harvesting as a Distributed Resource

2010 ◽  
Author(s):  
John H. Whear
Keyword(s):  
Distribution System ◽  
Distribution Systems ◽  
Water Distribution ◽  
Large Scale ◽  
Rainwater Harvesting ◽  
San Antonio ◽  
Water System ◽  
System Quality ◽  
Recycled Water

Explore the possibilities, difficulties, and benefits of large scale rainwater harvesting using recycled water distribution systems. This paper explores the growing use of recycled water and the possibilities that distribution systems have created. It investigates water quality of rainwater harvesting (RWH) systems and the quality of recycled water and their uses. It examines the amount of rain water available using aproximatly 10% of available roof area in the city and examines the benefits of large scale rainwater harvesting unique to San Antonio. An exhaustive search of published materials was conducted, coupled with communications with the Texas Water Development Board and the San Antonio Water System. Quality standards for recycled water were compared with known test results for harvested rainwater. With the use of mathematical models, a distributed rainwater harvesting systems was compared to a stand alone system. Connection to a distribution system reduces the cost of rainwater harvesting by eliminating the need for large amounts of storage, which can account for 50% of the total costs of a standalone system. With minor filtering and periodic quality checks, large structures may supply sufficient amounts of rainwater to justify being a source of water in a recycled water distribution system.

Biofilm formation in a hot water system

2002 ◽  
Vol 46 (9) ◽  
pp. 95-101 ◽  
Author(s):  
L.K. Bagh ◽  
H.-J. Albrechtsen ◽  
E. Arvin ◽  
K. Ovesen
Keyword(s):  
Distribution System ◽  
Biofilm Formation ◽  
Water Distribution ◽  
Water Distribution System ◽  
Formation Rate ◽  
Water System ◽  
Hot Water ◽  
Water Tank ◽  
Number Of Bacteria

The biofilm formation rate was measured in situ in a hot water system in an apartment building by specially designed sampling equipment, and the net growth of the suspended bacteria was measured by incubation of water samples with the indigeneous bacteria. The biofilm formation rate reached a higher level in the hot water distribution system (2.1 d−1 to 2.3 d−1) than in the hot water tank (1.4 d−1 to 2.2 d−1) indicating an important area for surface associated growth. The net growth rate of the suspended bacteria measured in hot water from the top, middle and bottom of the hot water tank, in the sludge, or in the water from the distribution system was negligible. This indicated that bacterial growth took place on the inner surfaces in the hot water system and biofilm formation and detachment of bacteria could account for most of the suspended bacteria actually measured in hot water. Therefore, attempts to reduce the number of bacteria in a hot water system have to include the distribution system as well as the hot water tank.

scholarly journals Interactive Visualisation of Water Distribution Network Optimisation

10.29007/x55c ◽  
2018 ◽  
Author(s):  
Matthew Johns ◽  
David Walker ◽  
Edward Keedwell ◽  
Dragan Savic
Keyword(s):  
Evolutionary Algorithms ◽  
Visual Analytics ◽  
Water Distribution ◽  
Distribution Network ◽  
Water System ◽  
Water Distribution Network ◽  
Water Systems ◽  
Network Optimisation ◽  
Water Distribution Network Design ◽  
Interactive Visualisation

Evolutionary algorithms have been used to optimize water systems in the literature for over three decades. However, their use for solving real-world water system problems in industry is still very limited. The work presented in this paper details the development of an interactive visualisation client for water distribution network design, which is part of a larger project to bring EAs closer to practicing engineers. The system aims at engaging engineers by actively involving them in the optimization process through the use of advanced visual analytics and novel interactive evolution techniques.

Role of Environmental Surveillance in Determining the Risk of Hospital-Acquired Legionellosis: A National Surveillance Study With Clinical Correlations

2007 ◽  
Vol 28 (7) ◽  
pp. 818-824 ◽  
Author(s):  
Janet E. Stout ◽  
Robert R. Muder ◽  
Sue Mietzner ◽  
Marilyn M. Wagener ◽  
Mary Beth Perri ◽  
...  
Keyword(s):  
Environmental Monitoring ◽  
Legionella Pneumophila ◽  
Distribution System ◽  
Water Distribution ◽  
Medical Center ◽  
Water System ◽  
Water Systems ◽  
Environmental Surveillance ◽  
Clinical Surveillance ◽  
Hospital Acquired

Objective.Hospital-acquired Legionella pneumonia has a fatality rate of 28%, and the source is the water distribution system. Two prevention strategies have been advocated. One approach to prevention is clinical surveillance for disease without routine environmental monitoring. Another approach recommends environmental monitoring even in the absence of known cases of Legionella pneumonia. We determined the Legionella colonization status of water systems in hospitals to establish whether the results of environmental surveillance correlated with discovery of disease. None of these hospitals had previously experienced endemic hospital-acquired Legionella pneumonia.Design.Cohort study.Setting.Twenty US hospitals in 13 states.Interventions.Hospitals performed clinical and environmental surveillance for Legionella from 2000 through 2002. All specimens were shipped to the Special Pathogens Laboratory at the Veterans Affairs Pittsburgh Medical Center.Results.Legionella pneumophila and Legionella anisa were isolated from 14 (70%) of 20 hospital water systems. Of 676 environmental samples, 198 (29%) were positive for Legionella species. High-level colonization of the water system (30% or more of the distal outlets were positive for L. pneumophila) was demonstrated for 6 (43%) of the 14 hospitals with positive findings. L. pneumophila serogroup 1 was detected in 5 of these 6 hospitals, whereas 1 hospital was colonized with L. pneumophila serogroup 5. A total of 633 patients were evaluated for Legionella pneumonia from 12 (60%) of the 20 hospitals: 377 by urinary antigen testing and 577 by sputum culture. Hospital-acquired Legionella pneumonia was identified in 4 hospitals, all of which were hospitals with L. pneumophila serogroup 1 found in 30% or more of the distal outlets. No cases of disease due to other serogroups or species (L. anisa) were identified.Conclusion.Environmental monitoring followed by clinical surveillance was successful in uncovering previously unrecognized cases of hospital-acquired Legionella pneumonia.

The PROCRUSTES testbed: tackling cyber-physical risk for water systems

2021 ◽  
Author(s):  
Georgios Moraitis ◽  
Dionysios Nikolopoulos ◽  
Ifigeneia Koutiva ◽  
Ioannis Tsoukalas ◽  
George Karavokiros ◽  
...  
Keyword(s):  
Risk Reduction ◽  
Water Distribution ◽  
Treatment Options ◽  
Water System ◽  
Water Distribution Network ◽  
Water Systems ◽  
Cyber Attacks ◽  
Water Utilities ◽  
Water Sector ◽  
Information Layer

<p>Our modern urban environment relies on critical infrastructures that serve vital societal functions, such as water supply and sanitation, which are exposed to various threats of both physical and cyber nature. Despite the progress in protection and increased vigilance, long-established practices within the water utilities may rely on precarious methods for the characterization and assessment of threats, with uncertainty pertaining to risk-relevant data and information. Sources for uncertainty can be attributed to e.g. limited capabilities of deterministic approaches, siloed analysis of water systems, use of ambiguous measures to describe and prioritise risks or common security misconceptions. To tackle those challenges, this work brings together an ensemble of solutions, to form a novel, unified process of resilience assessment for the water sector against an emerging cyber-physical threat landscape e.g., cyber-attacks on the command and control sub-system. Specifically, the proposed framework sets out an operational workflow that combines, inter alia, a) an Agent-Based Modelling (ABM) approach to derive alternative routes to quantify risks considering the dynamics of socio-technical systems, b) an adaptable optimisation platform which integrates advanced multi-objective algorithms for system calibration, uncertainty propagation analysis and asset criticality prioritization and c) a dynamic risk reduction knowledge-base (RRKB) designed to facilitate the identification and selection of suitable risk reduction measures (RRM). This scheme is overarched by a cyber-physical testbed, able to realistically model the interactions between the information layer (sensors, PLCs, SCADA) and the water distribution network. The testbed is designed to assess the water system beyond normal operational capacity. It facilitates the exploration of emergent and unidentified threats and vulnerabilities leading to Low Probability, High Consequence (LPHC) events that systems are not originally designed to handle. It also evaluates alternative risk treatment options against case-appropriate indicators. The final product is the accretion of actionable information to integrate risk into decision-making in a practical and standardized form. Our work envisions to bring forth state-of-art technologies and approaches for the cyber-wise water sector. We aspire to enhance existing capabilities for large utilities and enable small and medium water utilities with typically less resources, to reinforce their systems’ resilience and be better prepared against cyber-physical and other threats.</p>

Sewers and the Quality of Canals and Ditches in Amsterdam

1993 ◽  
Vol 27 (5-6) ◽  
pp. 61-67 ◽  
Author(s):  
E. Jacobs ◽  
J. W. van Sluis
Keyword(s):  
Water Quality ◽  
Surface Water ◽  
Sediment Quality ◽  
Water System ◽  
Water Systems ◽  
Sewer System ◽  
Water And Sediment ◽  
Combined Sewer ◽  
Water And Sediment Quality

The surface water system of Amsterdam is very complicated. Of two characteristic types of water systems the influences on water and sediment quality are investigated. The importance of the sewer output to the total loads is different for both water systems. In a polder the load from the sewers is much more important than in the canal basin. Measures to reduce the emission from the sewers are much more effective in a polder. The effect of these measures on sediment quality is more than the effect on water quality. Some differences between a combined sewer system and a separate sewer system can be found in sediment quality.

Design of rural water systems using dynamic models

1999 ◽  
Vol 39 (4) ◽  
pp. 221-231
Author(s):  
A. H. Lobbrecht
Keyword(s):  
Dynamic Models ◽  
Water System ◽  
Design Procedure ◽  
Real Data ◽  
Water Systems ◽  
Design Methods ◽  
Water Quality Criteria ◽  
Rural Water ◽  
Rural Water Systems ◽  
The Way

The properties of main water ways and infrastructure of rural water systems are often determined by very general design methods. These methods are based on standards that use only little information of the actual water system. Most design methods applied in the Netherlands are based on land use and soil texture. Standards have been developed on the basis of generalized properties of water systems. Details of the actual layout of the water system and the way in which that system is controlled, are usually not incorporated. Present-day dynamic simulation programs and the computer power currently available enable more detailed modeling and incorporation of location-specific data into models. Such models can be used to design the water system and can include real data. A model-based design method is introduced, in which the actual situation of the water system is taken into consideration as well as the way in which the water system is controlled. Stochastics concerning the operation and availability of controlling infrastructure are included in the method. Models can be evaluated by including real data. In this way the actual safety of the water system, for example during floods, can be determined. Water-quantity design criteria can be incorporated as well as water-quality criteria. Application of the method makes it possible to design safe water systems in which excess capacities are avoided and in which all requirements of interest are met. The method, called the ‘dynamic design procedure’, can result in considerable savings for water authorities when new systems have to be designed or existing designs have to be reconsidered.

A fluorescent aptasensor based on berberine for ultrasensitive detection of bisphenol A in tap water

2021 ◽  
Author(s):  
Yuxin Wei ◽  
Yangyang Zhou ◽  
Yanli Wei ◽  
Chuan Dong ◽  
Li Wang
Keyword(s):  
Bisphenol A ◽  
Human Health ◽  
Food Packaging ◽  
Tap Water ◽  
Water Systems ◽  
Ultrasensitive Detection ◽  
Its Analysis ◽  
Potential Impact ◽  
Fluorescent Aptasensor

The residues of bisphenol A (BPA) in food packaging and water systems have potential impact on human health, therefore, its analysis and detection has drawn people's attention. In this work,...

Sign in / Sign up

Export Citation Format

Share Document