Van Der Wielen P.W.J.J.,KWR Watercycle Research Institute |
Bakker G.,Vitens |
Atsma A.,Vitens |
Lut M.,Oasen |
And 2 more authors.
Environmental Science: Water Research and Technology | Year: 2016
The objective of our study was to explore microbiological parameters that are suitable as indicators for regrowth in distribution systems that receive unchlorinated drinking water in the Netherlands. Treated water and distributed water at two locations in the distribution system of 28 treatment plants were analyzed for a range of biological parameters. The results demonstrated that Aeromonas, HPCs, and Mycobacterium were significantly (more often) higher and ATP was significantly (more often) lower in the distributed water than in the treated water, whereas cell numbers remained stable during distribution. Average fungal 18S rRNA gene copies did not differ significantly between the treated and the distributed water, but fungal numbers were significantly more often higher in the distributed water than in the corresponding treated water. These results demonstrate that the distribution system has a clear effect on HPCs, Aeromonas, Mycobacterium, ATP and, to a lesser extent, on fungi in drinking water, but not on cell numbers. Furthermore, we noticed that ATP in the treated water is a better predictor for the regrowth level in the distribution system than total, membrane-intact or HNA cell numbers. In contrast to previous studies, we conclude that ATP and cell numbers seem to be poor indicators for regrowth in the drinking water environment, whereas HPCs, Aeromonas, Mycobacterium and, to a lesser extent, fungi appear to be more reliable indicators to monitor regrowth. © 2016 The Royal Society of Chemistry.
Roeselers G.,TNO |
Coolen J.,TNO |
van der Wielen P.W.J.J.,KWR Watercycle Research Institute |
Jaspers M.C.,TNO |
And 3 more authors.
Environmental Microbiology | Year: 2015
In this study, we collected water from different locations in 32 drinking water distribution networks in the Netherlands and analysed the spatial and temporal variation in microbial community composition by high-throughput sequencing of 16S rRNA gene amplicons. We observed that microbial community compositions of raw source and processed water were very different for each distribution network sampled. In each network, major differences in community compositions were observed between raw and processed water, although community structures of processed water did not differ substantially from end-point tap water. End-point water samples within the same distribution network revealed very similar community structures. Network-specific communities were shown to be surprisingly stable in time. Biofilm communities sampled from domestic water metres varied distinctly between households and showed no resemblance to planktonic communities within the same distribution networks. Our findings demonstrate that high-throughput sequencing provides a powerful and sensitive tool to probe microbial community composition in drinking water distribution systems. Furthermore, this approach can be used to quantitatively compare the microbial communities to match end-point water samples to specific distribution networks. Insight in the ecology of drinking water distribution systems will facilitate the development of effective control strategies that will ensure safe and high-quality drinking water. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.
Bakker M.,Technical University of Delft |
Bakker M.,Royal HaskoningDHV B.V. |
Trietsch E.A.,Vitens |
Vreeburg J.H.G.,Wageningen University |
And 2 more authors.
Water Science and Technology: Water Supply | Year: 2014
Pipe bursts in water distribution networks lead to water losses and a risk of damaging the urban environment. We studied hydraulic data and customer contact records of 44 real bursts for a better understanding of the phenomena. We found that most bursts were reported to the water company shortly after the beginning, and the negative consequences of the bursts were limited. However, smaller bursts that stayed unnoticed for a longer time period or larger bursts that began in the late evening or in the night were problematic to the water company that had no burst detection method installed. Detection of those bursts was critical to minimise the negative consequences, and a burst detection method could perform this task. We studied the relation between the size of supply area and the size of the bursts that can be detected. Therefore, we applied a heuristic burst detection method on historic datasets of eight areas varying in size between 1,500 and 48,300 connections. We found a correlation between the size of the area and the minimum detectable burst size and quickly detectable burst size. To reduce the risk of substantial water losses or damage to the urban environment, the burst detection method can effectively be applied to areas with an average demand of 150 m3/h or less. © IWA Publishing 2014.
Duiven J.,Vitens |
Rietman B.,Vitens |
Van De Ven W.,Vitens
Journal of Water Supply: Research and Technology - AQUA | Year: 2010
In treatment of groundwater with reverse osmosis, the applied antiscalant can significantly contribute to the formation of biofouling, especially when legislation enforces the use of biodegradable, phosphorous-free products. As an alternative to extensive piloting, the use of the membrane fouling simulator (MFS) is proposed here to assess the biomass growth potential of different antiscalants. The biomass growth potential of two newly developed, phosphorous-free antiscalants was compared to a blank (no antiscalant) and a phosphorous-based antiscalant. The difference in biomass growth potential in the four experiments was significant, with the phosphorous-based antiscalant showing little biomass accumulation and strong and moderate biomass accumulation for the two newly developed phosphorous-free antiscalants. The results of visual observation and pressure measurements of the MFS were compared to the results of autopsy of the membrane sheets. Visual and pressure measurements were found to be a more reliable method to judge the biomass accumulation than membrane autopsy. In a comparison study of MFSs and test rigs with 4″ spiral-wound membrane modules, similar results were found, validating MFS use for simulating membrane modules. © IWA Publishing 2010.
Van Vossen-Van Den Berg J.,KWR Watercycle Research Institute |
Blokker E.J.M.,KWR Watercycle Research Institute |
De Graaf B.,Vitens
Procedia Engineering | Year: 2015
Regulatory sampling programmes have a fairly small chance of detecting contamination events in the drinking water distribution network. Sensors have the ability to measure more frequently and recent advancements in microbial sensor technology allow for faster detection. Using a hydraulic model of an actual network it is shown that even small sensor networks have a far better chance of detecting contamination events than regulatory sampling programmes. This allows for more effective response strategies by drinking water companies, thereby reducing the health risk of potential faecal contaminations. © 2015 Published by Elsevier Ltd.
Williamson F.,Optiqua Technologies |
Van Den Broeke J.,Optiqua Technologies |
Koster T.,Optiqua Technologies |
Klein Koerkamp M.,Optiqua Technologies |
And 4 more authors.
Water Practice and Technology | Year: 2014
To ensure the safe supply of drinking water, the quality needs to be monitored online in real time. The consequence of inadequate monitoring can result in substantial health risks and economic and reputational damages. Therefore, Vitens, the largest drinking water company of the Netherlands, set a goal to explore and invest in the development of intelligent water supply by implementing a smart water grid. To enable this, Vitens has allocated a designated part of their distribution network to be a demonstration network for online water quality monitoring, the Vitens Innovation Playground (VIP). In the VIP, a network of 44 Optiqua EventLab sensors has been installed. EventLab utilizes refractive index as a generic parameter for continuous real-time monitoring of changes in water quality. The EventLab units in the network transmit their data by GPRS to Optiqua servers where the data are processed using event detection algorithms. Deployed as an online sensor network, it allows early detection and rapid response, as well as accurate location of the spread of a contamination within the distribution network. The use of the EventLab sensor network under operational conditions in the VIP is described and its effectiveness is demonstrated by the detection of two water quality events. © IWA Publishing 2014.
Blokker E.J.M.,KWR Watercycle Research Institute |
van Osch A.M.,Gemeente Almere |
Hogeveen R.,De Rookamer 6 |
Journal of Water and Climate Change | Year: 2013
The municipality of Almere is planning to develop a new carbon neutral neighbourhood. The area is located close to a treated water storage facility. By extracting enough thermal energy to provide 900 homes with energy for space heating and heating tap water, the temperature of the treated water is lowered by 1.16 WC. This could lead to an increase in the energy required to heat water for domestic purposes. The temperature of tap water is influenced by the temperature of the soil surrounding the drinking water distribution system. The rate at which the water temperature will reach the soil temperature depends on the pipe material, the pipe diameter and the flow velocity. With the help of a network model, the effect of a lower initial water temperature on every customer in Almere was determined. On average, all 75,000 connections would receive slightly cooler water. The energy to heat the extra 0.125 WC is equivalent to the energy required to heat approximately 85 homes. As the extracted thermal energy enables heating of 900 homes, the energy balance is very positive. © IWA Publishing 2013.
de Graaf B.R.,Vitens |
Williamson F.,Optiqua Technologies Pte Ltd |
Koerkamp M.K.,Optiqua Technologies Pte Ltd |
Verhoef J.W.,Optiqua Technologies Pte Ltd |
And 4 more authors.
Water Practice and Technology | Year: 2012
For safe supply of drinking water, water quality needs to be monitored online in real time. The consequence of inadequate monitoring can result in substantial health risks, and economic and reputational damages. Therefore, Vitens N.V., the largest drinking water company of the Netherlands, set a goal to explore and invest in the devel- opment of intelligent water supply. In order to do this Vitens N.V. has set up a demonstration network for online water quality monitoring, the Vitens Innovation Playground (VIP). With the recent innovative developments in the field of online sensoring Vitens kicked off, in 2011, its first major online sensoring program by implementing a sensor grid based on EventLab systems from Optiqua Technologies Pte Ltd in the distribution network. EventLab utilizes bulk refractive index as a generic parameter for continuous real time monitoring of changes in water qual- ity. Key characteristics of this innovative optical sensor technology, high sensitivity generic sensors at low cost, make it ideal for deployment as an early warning system. This paper describes different components of the system, the technological challenges that were overcome, and presents performance data and conclusions from deployment of Optiqua's EventLab systems in the VIP. © IWA Publishing 2012.
Scruton S.R.,Thekwini Water and Sanitation |
Bosboom J.,Your Man on Site |
29th International No-Dig Conference and Exhibition 2011, NO-DIG BERLIN 2011 | Year: 2011
This paper discusses the decision variables to be evaluated for the rehabilitation of water mains, considering the performance of the network, the economic and technical lifespan of the mains and different available trenchless technologies in comparison to 'open trench' methodology. Water mains have a natural rate of attrition and they deteriorate over time. All Water Utilities / Municipalities in South Africa have been mandated by the National Government to efficiently manage their assets. The replacement of pipes is the most expensive intervention and therefore it is critically important to ensure that the correct water mains are targeted for renewal or rehabilitation and with the right available technology. To do this a number of key performance indicators need to be monitored on a permanent basis and these are determined by the specific requirements of the Water Utility. The rehabilitation or renewal of these assets can thus be reliably predicted to maximize the benefits and adequate budget can be allocated. Co-funded by the Dutch Government, eThekwini Water and Sanitation have committed themselves to do a comprehensive pilot study to compare different rehabilitation techniques on technical, operational, economic, and socio-economic aspects. Importantly, the research will also determine the measures to be undertaken to extend the life of an existing water main and thereby delay the date when the main will need to be replaced. It will further document the specific variables to be assessed in determining when a water main needs to be renewed or rehabilitated and with which technology. The outcome of this research will greatly enhance the ability of Water Utilities to maximize the performance of their networks by striking the best balance between capital and operational expenditure whilst taking into account the requirements of risk of failure and the cost of the rehabilitation / replacement.
PubMed | University of Amsterdam, KWR Watercycle Research Institute, Vitens and Applied Scientific Research
Type: | Journal: The Science of the total environment | Year: 2016
Only very limited information is available on measured environmental concentrations of nanoparticles. In this study, several environmental compartments in The Netherlands were probed for the presence of nanoparticles. Different types of water were screened for the presence of inorganic (Ag, Au, TiO