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

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.

scholarly journals Reference pathogen numbers in urban stormwater for drinking water risk assessment

2015 ◽  
Vol 6 (1) ◽  
pp. 30-39 ◽  
Author(s):  
D. W. Page ◽  
K. Barry ◽  
D. Gonzalez ◽  
A. Keegan ◽  
P. Dillon
Keyword(s):  
Risk Assessment ◽  
Drinking Water ◽  
Open Space ◽  
Microbial Inactivation ◽  
Control Measures ◽  
Quantitative Microbial Risk Assessment ◽  
Log10 Reduction ◽  
Urban Stormwater ◽  
Microbial Risk Assessment ◽  
Microbial Risk

Targeted stormwater event-based monitoring of adenovirus, Cryptosporidium and Campylobacter, the human health reference pathogens of viruses, protozoa and bacteria, respectively, was undertaken to determine numbers prior to water recycling via an aquifer. This allowed the determination of a 95th percentile of reference pathogen numbers in stormwater (2 n/L for adenoviruses, 1.4 n/L for Cryptosporidium and 11 n/L for Campylobacter) and was used in a quantitative microbial risk assessment to determine the required microbial inactivation targets. Log10 removals through treatments and/or control measures to manage pathogen risks were determined for different end uses based on the 95th percentile numbers. Public open space irrigation was found to require 1.6 log10 reduction for viruses, 0.6 log10 for protozoa and 1.2 log10 for bacteria; third pipe systems which include potential exposure through toilet flushing and washing machine use require 2.7 log10 reduction for viruses, 1.8 log10 for protozoa and 2.3 log10 for bacteria; and drinking water requires 5.8 log10 reduction for viruses, 4.8 log10 for protozoa and 5.3 log10 for bacteria. These results are the first reported for an Australian urban stormwater site with sufficient data for a drinking water risk assessment.

scholarly journals Quantitative Microbial Risk Assessment of Drinking Water Quality to Predict the Risk of Waterborne Diseases in Primary-School Children

2020 ◽  
Vol 17 (8) ◽  
pp. 2774 ◽  
Author(s):  
Jamil Ahmed ◽  
Li Ping Wong ◽  
Yan Piaw Chua ◽  
Najeebullah Channa ◽  
Rasool Bux Mahar ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Drinking Water ◽  
Primary School ◽  
School Children ◽  
Primary School Children ◽  
Quantitative Microbial Risk Assessment ◽  
Waterborne Diseases ◽  
Salmonella Spp ◽  
Microbial Risk Assessment ◽  
Microbial Risk

Primary-school children in low- and middle-income countries are often deprived of microbiologically safe water and sanitation, often resulting in a high prevalence of gastrointestinal diseases and poor school performance. We used Quantitative Microbial Risk Assessment (QMRA) to predict the probability of infection in schoolchildren due to consumption of unsafe school water. A multistage random-sampling technique was used to randomly select 425 primary schools from ten districts of Sindh, Pakistan, to produce a representative sample of the province. We characterized water supplies in selected schools. Microbiological testing of water resulted in inputs for the QMRA model, to estimate the risks of infections to schoolchildren. Groundwater (62%) and surface water (38%) were identified as two major sources of drinking water in the selected schools, presenting varying degrees of health risks. Around half of the drinking-water samples were contaminated with Escherichia coli (49%), Shigella spp. (63%), Salmonella spp. (53%), and Vibrio cholerae (49%). Southern Sindh was found to have the highest risk of infection and illness from Campylobacter and Rotavirus. Central and Northern Sindh had a comparatively lower risk of waterborne diseases. Schoolchildren of Karachi were estimated to have the highest probability of illness per year, due to Campylobacter (70%) and Rotavirus (22.6%). Pearson correlation was run to assess the relationship between selected pathogens. V. cholerae was correlated with Salmonella spp., Campylobacter, Rotavirus, and Salmonella spp. Overall, the risk of illness due to the bacterial infection (E. coli, Salmonella spp., V. cholerae, Shigella, and Campylobacter) was high. There is a dire need for management plans in the schools of Sindh, to halt the progression of waterborne diseases in school-going children.

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.

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