Stochastic Modelling of Drinking Water Treatment in Quantitative Microbial Risk Assessment

2010 ◽  
Vol 9 ◽  
Author(s):  
Patrick W.M.H. Smeets
Keyword(s):  
Risk Assessment ◽  
Drinking Water ◽  
Water Treatment ◽  
Drinking Water Treatment ◽  
Stochastic Modelling ◽  
Quantitative Microbial Risk Assessment ◽  
Microbial Risk Assessment ◽  
Microbial Risk

Scenario-based quantitative microbial risk assessment to evaluate the robustness of a drinking water treatment plant

2016 ◽  
Vol 51 (2) ◽  
pp. 81-96 ◽  
Author(s):  
Mohamed A. Hamouda ◽  
William B. Anderson ◽  
Michele I. Van Dyke ◽  
Ian P. Douglas ◽  
Stéphanie D. McFadyen ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Drinking Water ◽  
Water Treatment ◽  
Treatment Plant ◽  
Water Treatment Plant ◽  
Operating Conditions ◽  
Quantitative Microbial Risk Assessment ◽  
Microbial Risk Assessment ◽  
Microbial Risk ◽  
Treatment Processes

While traditional application of quantitative microbial risk assessment (QMRA) models usually stops at analyzing the microbial risk under typical operating conditions, this paper proposes the use of scenario-based risk assessment to predict the impact of potential challenges on the expected risk. This study used a QMRA model developed by Health Canada to compare 14 scenarios created to assess the increase in risk due to potential treatment failures and unexpected variations in water quality and operating parameters of a water treatment plant. Under regular operating conditions, the annual risk of illness was found to be substantially lower than the acceptable limit. Scenario-based QMRA was shown to be useful in demonstrating which hypothetical treatment failures would be the most critical, resulting in an increased risk of illness. The analysis demonstrated that scenarios incorporating considerable failure in treatment processes resulted in risk levels surpassing the acceptable limit. This reiterates the importance of robust treatment processes and the multi-barrier approach voiced in drinking water safety studies. Knowing the probability of failure, and the risk involved, allows designers and operators to make effective plans for response to treatment failures and/or recovery actions involving potential exposures. This ensures the appropriate allocation of financial and human resources.

Quantitative microbial risk assessment of a drinking water – wastewater cross-connection simulation

2008 ◽  
Vol 7 (5) ◽  
pp. 525-530 ◽  
Author(s):  
Kristina D. Mena ◽  
Linda C. Mota ◽  
Mark C. Meckes ◽  
Christopher F. Green ◽  
William W. Hurd ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Drinking Water ◽  
Quantitative Microbial Risk Assessment ◽  
Microbial Risk Assessment ◽  
Microbial Risk ◽  
Cross Connection

scholarly journals Characterizing the concentration of Cryptosporidium in Australian surface waters for setting health-based targets for drinking water treatment

2015 ◽  
Vol 13 (3) ◽  
pp. 879-896 ◽  
Author(s):  
S. Petterson ◽  
D. Roser ◽  
D. Deere
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Physiological State ◽  
Drinking Water Treatment ◽  
World Health ◽  
Quantitative Microbial Risk Assessment ◽  
Surface Source ◽  
Microbial Risk Assessment ◽  
Treatment Targets ◽  
Climatic Regions

It is proposed that the next revision of the Australian Drinking Water Guidelines will include ‘health-based targets’, where the required level of potable water treatment quantitatively relates to the magnitude of source water pathogen concentrations. To quantify likely Cryptosporidium concentrations in southern Australian surface source waters, the databases for 25 metropolitan water supplies with good historical records, representing a range of catchment sizes, land use and climatic regions were mined. The distributions and uncertainty intervals for Cryptosporidium concentrations were characterized for each site. Then, treatment targets were quantified applying the framework recommended in the World Health Organization Guidelines for Drinking-Water Quality 2011. Based on total oocyst concentrations, and not factoring in genotype or physiological state information as it relates to infectivity for humans, the best estimates of the required level of treatment, expressed as log10 reduction values, ranged among the study sites from 1.4 to 6.1 log10. Challenges associated with relying on historical monitoring data for defining drinking water treatment requirements were identified. In addition, the importance of quantitative microbial risk assessment input assumptions on the quantified treatment targets was investigated, highlighting the need for selection of locally appropriate values.

Quantitative microbial risk assessment (QMRA) to support decisions for water supply in affluent and developing countries

2019 ◽  
Vol 14 (3) ◽  
pp. 542-548 ◽  
Author(s):  
P. W. M. H. Smeets
Keyword(s):  
Risk Assessment ◽  
Developing Countries ◽  
Drinking Water ◽  
Water Supply ◽  
Quantitative Microbial Risk Assessment ◽  
Microbial Risk Assessment ◽  
Microbial Risk ◽  
The Past ◽  
Relative Risks ◽  
Microbial Risks

Abstract Providing microbially safe water is a main goal of water supply to prevent endemic waterborne disease and outbreaks. Since increasing the level of safety requires resources, it is important to identify most relevant risks and efficient ways to reach health-based targets. Over the past decades, quantitative microbial risk assessment (QMRA) developed into a systematic, science-based approach to assess microbial risks through drinking water supply. In this study we present the QMRA approach and how it can be used to support decisions in both affluent and developing countries. This includes examples from the statutory QMRA in the Netherlands that led to efficient and effective improvements in water supply, not only in treatment, but also in monitoring and operation. In developing countries people often need to use various sources of drinking water. We will demonstrate how QMRA can help to improve insight in the relative risks of these routes and the effect of interventions.

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