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- Malm, Annika, 1970, et al.
(author)
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Replacement predictions for drinking water networks through historical data
- 2012
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In: Water Research. - : Elsevier BV. - 0043-1354 .- 1879-2448. ; 46:7, s. 2149-2158
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Journal article (peer-reviewed)abstract
- Lifetime distribution functions and current network age data can be combined to provide an assessment of the future replacement needs for drinking water distribution networks. Reliable lifetime predictions are limited by a lack of understanding of deterioration processes for different pipe materials under varied conditions. An alternative approach is the use of real historical data for replacement over an extended time series. In this paper, future replacement needs are predicted through historical data representing more than one hundred years of drinking water pipe replacement in Gothenburg, Sweden. The verified data fits well with commonly used lifetime distribution curves. Predictions for the future are discussed in the context of path dependence theory.
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- Nilsson, Per, et al.
(author)
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SCADA data and the quantification of hazardous events for QMRA
- 2007
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In: Journal of Water and Health. - : IWA Publishing. - 1477-8920 .- 1996-7829. ; 5, s. 99-105
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Journal article (peer-reviewed)abstract
- The objective of this study was to assess the use of on-line monitoring to support the QMRA at water treatment plants studied in the EU MicroRisk project. SCADA data were obtained from diary records, grab three Catchment-to-Tap Systems (CTS) along with system descriptions, sample data and deviation reports. Particular attention was paid to estimating hazardous event frequency, duration and magnitude. Using Shewart and CUSUM we identified 'change-points' corresponding to events of between 10 min and > 1 month duration in timeseries data. Our analysis confirmed it is possible to quantify hazardous event durations from turbidity, chlorine residual and pH records and distinguish them from non-hazardous variability in the timeseries dataset. The durations of most 'events' were short-term (0.5-2.3 h). These data were combined with QMRA to estimate pathogen infection risk arising from such events as chlorination failure. its interpretation was While analysis of SCADA data alone could identify events provisionally, severely constrained in the absence of diary records and other system information. SCADA data analysis should only complement traditional water sampling, rather than replace it. More work on on-line data management, quality control and interpretation is needed before it can be used for event characterization routinely for event characterrisation.
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- Saguti, Fredy, et al.
(author)
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The Virucidal Effect of the Chlorination of Water at the Initial Phase of Disinfection May Be Underestimated If Contact Time Calculations Are Used
- 2023
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In: Pathogens. - 2076-0817. ; 12:10
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Journal article (peer-reviewed)abstract
- For the microbiological safety of drinking water, disinfection methods are used to remove or inactivate microorganisms. Chlorine and chlorine dioxide are often used as disinfectants in drinking water treatment plants (DWTPs). We investigated the effectiveness of these chemicals in inactivate echovirus 30 (E30), simian 11 rotavirus (RV SA11), and human adenovirus type 2 (HAdV2) in purified water from a DWTP. Within two minutes of contact, chlorine dioxide inactivated E30 by 4-log10, RV SA11 by 3-log10, and HAdV2 could not be detected, while chlorine reduced E30 by 3-log10, RV SA11 by 2-3log10, and HAdV2 by 3-4log10. However, viral genomes could be detected for up to 2 h using qPCR. The CT method, based on a combination of disinfectant concentration and contact time, during such a short initial phase, is problematic. The high concentrations of disinfectant needed to neutralize organic matter may have a strong immediate effect on virus viability. This may lead to the underestimation of disinfection and overdosing of disinfectants in water with organic contamination. These results are useful for the selection of disinfection systems for reuse of treated wastewater and in the risk assessment of water treatment processes using chlorine and chlorine dioxide.
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