Human Health Impact of Cross-Connections in Non-Potable Reuse Systems

We used quantitative microbial risk assessment (QMRA) to estimate the microbial risks from two contamination pathways in onsite non-potable water systems (ONWS): contamination of potable water by (treated) reclaimed, non-potable water and contamination of reclaimed, non-potable water by wastewater or greywater. A range of system sizes, event durations, fraction of users exposed, and intrusion dilutions were considered (chlorine residual disinfection was not included). The predicted annual microbial infection risk from domestic, non-potable reuse remained below the selected benchmark given isolated, short-duration intrusion (i.e., 5-day) events of reclaimed water in potable water. Whereas, intrusions of wastewater into reclaimed, non-potable water resulted in unacceptable annual risk without large dilutions or pathogen inactivation. We predicted that 1 user out of 10,000 could be exposed to a 5-day contamination event of undiluted wastewater in the reclaimed, non-potable water system each year to meet the annual benchmark risk of 10−4 infections per person per year; whereas, 1 user out of 1000 could be exposed to a 5-day contamination event of undiluted reclaimed water in the potable water each year. Overall, the predicted annual risks support the use of previously derived non-potable reuse treatment requirements for a variety of ONWS sizes and support the prioritization of protective measures to prevent the intrusion of wastewater into domestic ONWS.

Download Full-text

Quantitative microbial risk assessment of North Carolina reclaimed water for potable reuse

AWWA Water Science ◽

10.1002/aws2.1200 ◽

2020 ◽

Vol 2 (5) ◽

Author(s):

Emily S. Bailey ◽

Lisa M. Casanova ◽

Mark D. Sobsey

Keyword(s):

Risk Assessment ◽

North Carolina ◽

Reclaimed Water ◽

Quantitative Microbial Risk Assessment ◽

Microbial Risk Assessment ◽

Microbial Risk ◽

Potable Reuse

Download Full-text

Quantitative microbial risk assessment of a non-membrane based indirect potable water reuse system using Bayesian networks

The Science of The Total Environment ◽

10.1016/j.scitotenv.2021.146462 ◽

2021 ◽

Vol 780 ◽

pp. 146462

Author(s):

Veronika Zhiteneva ◽

Guido Carvajal ◽

Omar Shehata ◽

Uwe Hübner ◽

Jörg E. Drewes

Keyword(s):

Risk Assessment ◽

Bayesian Networks ◽

Water Reuse ◽

Potable Water ◽

Quantitative Microbial Risk Assessment ◽

Microbial Risk Assessment ◽

Microbial Risk ◽

Reuse System

Download Full-text

Quantitative Microbial Risk Analysis to evaluate health effects of interventions in the urban water system of Accra, Ghana

Journal of Water and Health ◽

10.2166/wh.2010.021 ◽

2010 ◽

Vol 8 (3) ◽

pp. 417-430 ◽

Cited By ~ 37

Author(s):

Herve Labite ◽

Isabella Lunani ◽

Peter van der Steen ◽

Kala Vairavamoorthy ◽

Pay Drechsel ◽

...

Keyword(s):

Disease Burden ◽

Water System ◽

Reference Value ◽

Urban Water ◽

Quantitative Microbial Risk Assessment ◽

Indicator Organisms ◽

Microbial Risk Assessment ◽

Microbial Risk ◽

Urban Water System ◽

Life Years

A quantitative microbial risk assessment was applied to evaluate the microbial risks of the Accra Urban Water System (AUWS). The exposure assessment was based on the count of indicator organisms in waste water from open roadside drains and in water and sand samples from the beach. The predicted total disease burden generated in a representative catchment of the AUWS (Odaw Catchment) was 36,329 Disability Adjusted Life Years (DALYs) per year, of which 12 and 88% are caused by, respectively, shortcomings in the water supply system and inappropriate sanitation. The DALYs per person per year were above the WHO reference value. The open roadside drain had the highest contribution to the disease burden. Of four possible interventions evaluated for health risk reduction, the highest efficiency in terms of DALYs averted per euro invested would be achieved by providing covers for the open roadside drains.

Download Full-text

Application of QMRA to MAR operations for safe agricultural reuse and marine recreational impacts in coastal areas

10.5194/egusphere-egu2020-7208 ◽

2020 ◽

Author(s):

Costantino Masciopinto ◽

Michele Vurro ◽

Nicola Lorusso ◽

Domenico Santoro ◽

Charles N. Haas

Keyword(s):

Reclaimed Water ◽

Additional Treatment ◽

Soil Aquifer Treatment ◽

Quantitative Microbial Risk Assessment ◽

Aquifer Recharge ◽

Fractured Aquifer ◽

Microbial Risk Assessment ◽

Microbial Risk ◽

Pathogen Transport ◽

Vegetables And Fruits

The Municipality of Fasano (Puglia, Italy), i.e. owning one of 32 managed aquifer recharge (MAR) sites in operation in the Puglia region, has pioneered the reuse of tertiary-treated municipal effluent for both soil irrigations and the containment of seawater intrusion via groundwater recharge by ditches.In this work, quantitative microbial risk assessment (QMRA) methodologies have been applied to assess the degree of safety associated with such integrated practices by assessing the risks for public health resulting from the exposure to the reclaimed water. Escherichia coli (E.coli) dose-response model was used in this work since the pathogenic E.coli is reported to potentially occur in reclaimed water obtained from treated municipal effluents. The target count of pathogens ingested during swimming or inoculated by contaminated (uncooked) vegetables and fruits, was determined from the Monte Carlo Markov Chain (MCMC) Bayesian procedure applied to the results obtained from a monitoring campaign carried out in 2019. An optimization routine was applied in order to determine the most probable target pathogen count by minimizing the number of water samplings. The monitoring positions along the coast were defined by means of mathematical modeling, which highlighted the preferential pathways followed by pathogens when released into the fractured aquifer at a recharge operation flow rate of 10-30 L/s.QMRA results indicated a negligible risk impact (12% probability of 0.4 infections per year) for soil irrigation practices and no impact on the seawater quality as a result of the additional treatment barrier provided by the so-called "soil-aquifer treatment" during the pathogen transport through the fractures of groundwater.&#160;

Download Full-text

The Regeneration Water Research Based on the Characteristics of Jiangnan Water in the Green Ecological Building Area

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.209-211.492 ◽

2012 ◽

Vol 209-211 ◽

pp. 492-495

Author(s):

Dong Ying Xu ◽

Si Yuan Luo ◽

Meng Jie Jiang ◽

Xu Zhi Fang

Keyword(s):

Potable Water ◽

Biological Membrane ◽

Reclaimed Water ◽

Water System ◽

Membrane System ◽

Raw Water ◽

Recycled Water ◽

Building Area ◽

The Village ◽

Ecological Building

The recycled water is the important way to solve the shortage of water resources. In China the recycled water use in the jiangnan region is still in start level, rare setting up reclaimed water system inside the village . According to designing water system in jiangnan area, using the high quality miscellaneous drainage for raw water, filtering the all sizes of particle in water, and adopting the biological membrane system decompose the organic therein, the water after disinfection can be as the non potable water. This water system is simple in technology, not occupying the land, four years of recyclable cost and the operation maintenance costs are low.

Download Full-text

Quantitative Microbial Risk Assessment Models for Consumption of Raw Vegetables Irrigated with Reclaimed Water

Applied and Environmental Microbiology ◽

10.1128/aem.72.5.3284-3290.2006 ◽

2006 ◽

Vol 72 (5) ◽

pp. 3284-3290 ◽

Cited By ~ 158

Author(s):

Andrew J. Hamilton ◽

Frank Stagnitti ◽

Robert Premier ◽

Anne-Maree Boland ◽

Glenn Hale

Keyword(s):

Risk Assessment ◽

Reclaimed Water ◽

Quantitative Microbial Risk Assessment ◽

Risk Of Infection ◽

Worst Case ◽

Microbial Risk Assessment ◽

Microbial Risk ◽

Risk Assessment Models ◽

Crop Type ◽

Annual Risk

ABSTRACT Quantitative microbial risk assessment models for estimating the annual risk of enteric virus infection associated with consuming raw vegetables that have been overhead irrigated with nondisinfected secondary treated reclaimed water were constructed. We ran models for several different scenarios of crop type, viral concentration in effluent, and time since last irrigation event. The mean annual risk of infection was always less for cucumber than for broccoli, cabbage, or lettuce. Across the various crops, effluent qualities, and viral decay rates considered, the annual risk of infection ranged from 10−3 to 10−1 when reclaimed-water irrigation ceased 1 day before harvest and from 10−9 to 10−3 when it ceased 2 weeks before harvest. Two previously published decay coefficients were used to describe the die-off of viruses in the environment. For all combinations of crop type and effluent quality, application of the more aggressive decay coefficient led to annual risks of infection that satisfied the commonly propounded benchmark of ≤10−4, i.e., one infection or less per 10,000 people per year, providing that 14 days had elapsed since irrigation with reclaimed water. Conversely, this benchmark was not attained for any combination of crop and water quality when this withholding period was 1 day. The lower decay rate conferred markedly less protection, with broccoli and cucumber being the only crops satisfying the 10−4 standard for all water qualities after a 14-day withholding period. Sensitivity analyses on the models revealed that in nearly all cases, variation in the amount of produce consumed had the most significant effect on the total uncertainty surrounding the estimate of annual infection risk. The models presented cover what would generally be considered to be worst-case scenarios: overhead irrigation and consumption of vegetables raw. Practices such as subsurface, furrow, or drip irrigation and postharvest washing/disinfection and food preparation could substantially lower risks and need to be considered in future models, particularly for developed nations where these extra risk reduction measures are more common.

Download Full-text

Long-Range Planning for Water Reuse in the City of Los Angeles

Water Science & Technology ◽

10.2166/wst.1991.0231 ◽

1991 ◽

Vol 24 (9) ◽

pp. 11-17 ◽

Cited By ~ 3

Author(s):

Bahman Sheikh

Keyword(s):

Los Angeles ◽

Groundwater Recharge ◽

Water Reuse ◽

Potable Water ◽

Reclaimed Water ◽

Potable Reuse ◽

Water Demands ◽

San Fernando ◽

Near Term

While new sources of affordable potable water for Los Angeles will likely decrease or be unavailable in the future, sources of readily usable reclaimed water will double over the next decade. For many non-potable uses (e.g., landscape irrigation, industrial cooling, toilet flushing), reclaimed water can replace potable water, thereby making equivalent volumes of potable water available. Groundwater recharge with reclaimed water can further augment potable water supplies in significant volumes. Quantitative goals for water reuse were derived by comparing projected water demands with predicted dependable supplies. These goals are to reuse 40, 70, and 80 percent of the total effluent by the years 2010, 2050, and 2090, respectively. In this planning study, several water reuse concepts were evaluated for near-, mid-, and long-term application. For the near-term, several immediately implementable water reuse projects are recommended, involving landscape irrigation, industrial cooling and groundwater recharge. For the mid-term, massive groundwater recharge in San Fernando Valley and in Central and West Coast Basins is recommended. For the long-term, potable reuse and/or groundwater recharge appear to be the best options.

Download Full-text

QMRAspot: A tool for Quantitative Microbial Risk Assessment from surface water to potable water

Water Research ◽

10.1016/j.watres.2011.08.024 ◽

2011 ◽

Vol 45 (17) ◽

pp. 5564-5576 ◽

Cited By ~ 81

Author(s):

Jack F. Schijven ◽

Peter F.M. Teunis ◽

Saskia A. Rutjes ◽

Martijn Bouwknegt ◽

Ana Maria de Roda Husman

Keyword(s):

Risk Assessment ◽

Surface Water ◽

Potable Water ◽

Quantitative Microbial Risk Assessment ◽

Microbial Risk Assessment ◽

Microbial Risk

Download Full-text

A dose response model for Staphylococcus aureus

Scientific Reports ◽

10.1038/s41598-021-91822-y ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Srikiran Chandrasekaran ◽

Sunny C. Jiang

Keyword(s):

Staphylococcus Aureus ◽

Dose Response ◽

Current Approach ◽

Quantitative Microbial Risk Assessment ◽

Microbial Infection ◽

Antibiotic Resistant ◽

Response Models ◽

Microbial Risk Assessment ◽

Microbial Risk ◽

Mechanistic Basis

AbstractDose-response models (DRMs) are used to predict the probability of microbial infection when a person is exposed to a given number of pathogens. In this study, we propose a new DRM for Staphylococcus aureus (SA), which causes skin and soft-tissue infections. The current approach to SA dose-response is only partially mechanistic and assumes that individual bacteria do not interact with each other. Our proposed two-compartment (2C) model assumes that bacteria that have not adjusted to the host environment decay. After adjusting to the host, they exhibit logistic/cooperative growth, eventually causing disease. The transition between the adjusted and un-adjusted states is a stochastic process, which the 2C DRM explicitly models to predict response probabilities. By fitting the 2C model to SA pathogenesis data, we show that cooperation between individual SA bacteria is sufficient (and, within the scope of the 2C model, necessary) to characterize the dose-response. This is a departure from the classical single-hit theory of dose-response, where complete independence is assumed between individual pathogens. From a quantitative microbial risk assessment standpoint, the mechanistic basis of the 2C DRM enables transparent modeling of dose-response of antibiotic-resistant SA that has not been possible before. It also enables the modeling of scenarios having multiple/non-instantaneous exposures, with minimal assumptions.

Download Full-text