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Denpetkul T, Pumkaew M, Sittipunsakda O, Srathongneam T, Mongkolsuk S, Sirikanchana K. Risk-based critical concentrations of enteric pathogens for recreational water criteria and recommended minimum sample volumes for routine water monitoring. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 950:175234. [PMID: 39102962 DOI: 10.1016/j.scitotenv.2024.175234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2024] [Revised: 07/30/2024] [Accepted: 08/01/2024] [Indexed: 08/07/2024]
Abstract
Concerns are rising about the contamination of recreational waters from human and animal waste, along with associated risks to public health. However, existing guidelines for managing pathogens in these environments have not yet fully integrated risk-based pathogen-specific criteria, which, along with recent advancements in indicators and markers, are essential to improve the protection of public health. This study aimed to establish risk-based critical concentration benchmarks for significant enteric pathogens, i.e., norovirus, rotavirus, adenovirus, Cryptosporidium spp., Giardia lamblia, Campylobacter jejuni, Salmonella spp., and Escherichia coli O157:H7. Applying a 0.036 risk benchmark to both marine and freshwater environments, the study identified the lowest critical concentrations for children, who are the most susceptible group. Norovirus, C. jejuni, and Cryptosporidium presented lowest median critical concentrations for virus, bacteria, and protozoa, respectively: 0.74 GC, 1.73 CFU, and 0.39 viable oocysts per 100 mL in freshwater for children. These values were then used to determine minimum sample volumes corresponding to different recovery rates for culture method, digital polymerase chain reaction and quantitative PCR methods. The results indicate that for children, norovirus required the largest sample volumes of freshwater and marine water (52.08 to 178.57 L, based on the 5th percentile with a 10 % recovery rate), reflecting its low critical concentration and high potential for causing illness. In contrast, adenovirus and rotavirus required significantly smaller volumes (approximately 0.24 to 1.33 L). C. jejuni and Cryptosporidium, which required the highest sampling volumes for bacteria and protozoa, needed 1.72 to 11.09 L and 4.17 to 25.51 L, respectively. Additionally, the presented risk-based framework could provide a model for establishing pathogen thresholds, potentially guiding the creation of extensive risk-based criteria for various pathogens in recreational waters, thus aiding public health authorities in decision-making, strengthening pathogen monitoring, and improving water quality testing accuracy for enhanced health protection.
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Affiliation(s)
- Thammanitchpol Denpetkul
- Department of Social and Environmental Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand
| | - Monchai Pumkaew
- Environmental Engineering and Disaster Management Program, School of Multidisciplinary, Mahidol University, Kanchanaburi Campus, Kanchanaburi 71150, Thailand
| | - Oranoot Sittipunsakda
- Department of Social and Environmental Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand
| | - Thitima Srathongneam
- Research Laboratory of Biotechnology, Chulabhorn Research Institute, Bangkok 10210, Thailand
| | - Skorn Mongkolsuk
- Research Laboratory of Biotechnology, Chulabhorn Research Institute, Bangkok 10210, Thailand; Center of Excellence on Environmental Health and Toxicology (EHT), OPS, MHESI, Bangkok 10400, Thailand
| | - Kwanrawee Sirikanchana
- Research Laboratory of Biotechnology, Chulabhorn Research Institute, Bangkok 10210, Thailand; Center of Excellence on Environmental Health and Toxicology (EHT), OPS, MHESI, Bangkok 10400, Thailand.
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2
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Jahne MA, Schoen ME, Kaufmann A, Pecson BM, Olivieri A, Sharvelle S, Anderson A, Ashbolt NJ, Garland JL. Enteric pathogen reduction targets for onsite non-potable water systems: A critical evaluation. WATER RESEARCH 2023; 233:119742. [PMID: 36848851 PMCID: PMC10084472 DOI: 10.1016/j.watres.2023.119742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 02/10/2023] [Accepted: 02/11/2023] [Indexed: 06/18/2023]
Abstract
Onsite non-potable water systems (ONWS) collect and treat local source waters for non-potable end uses such as toilet flushing and irrigation. Quantitative microbial risk assessment (QMRA) has been used to set pathogen log10-reduction targets (LRTs) for ONWS to achieve the risk benchmark of 10-4 infections per person per year (ppy) in a series of two efforts completed in 2017 and 2021. In this work, we compare and synthesize the ONWS LRT efforts to inform the selection of pathogen LRTs. For onsite wastewater, greywater, and stormwater, LRTs for human enteric viruses and parasitic protozoa were within 1.5-log10 units between 2017 and 2021 efforts, despite differences in approaches used to characterize pathogens in these waters. For onsite wastewater and greywater, the 2017 effort used an epidemiology-based model to simulate pathogen concentrations contributed exclusively from onsite waste and selected Norovirus as the viral reference pathogen; the 2021 effort used municipal wastewater pathogen data and cultivable adenoviruses as the reference viral pathogen. Across source waters, the greatest differences occurred for viruses in stormwater, given the newly available municipal wastewater characterizations used for modeling sewage contributions in 2021 and the different selection of reference pathogens (Norovirus vs. adenoviruses). The roof runoff LRTs support the need for protozoa treatment, but these remain difficult to characterize due to the pathogen variability in roof runoff across space and time. The comparison highlights adaptability of the risk-based approach, allowing for updated LRTs as site specific or improved information becomes available. Future research efforts should focus on data collection of onsite water sources.
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Affiliation(s)
- Michael A Jahne
- Office of Research and Development, U.S. Environmental Protection Agency, 26 W. Martin Luther King Dr., Cincinnati, OH 45268, USA.
| | - Mary E Schoen
- Soller Environmental, LLC, 3022 King St., Berkeley, CA 94703, USA
| | - Anya Kaufmann
- Trussell Technologies, Inc., 1939 Harrison St., Oakland, CA 94612, USA
| | - Brian M Pecson
- Trussell Technologies, Inc., 1939 Harrison St., Oakland, CA 94612, USA
| | | | - Sybil Sharvelle
- Colorado State University, Department of Civil and Environmental Engineering, 1372 Campus Delivery, Fort Collins, CO 80523, USA
| | - Anita Anderson
- Minnesota Department of Health, 625 Robert St. N, St. Paul, MN 55164, USA
| | | | - Jay L Garland
- Office of Research and Development, U.S. Environmental Protection Agency, 26 W. Martin Luther King Dr., Cincinnati, OH 45268, USA
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3
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Zhiteneva V, Carvajal G, Shehata O, Hübner U, Drewes JE. Quantitative microbial risk assessment of a non-membrane based indirect potable water reuse system using Bayesian networks. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 780:146462. [PMID: 33774303 DOI: 10.1016/j.scitotenv.2021.146462] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 03/07/2021] [Accepted: 03/10/2021] [Indexed: 06/12/2023]
Abstract
Risk-based approaches are used to define performance standards for water and wastewater treatment to meet health-based targets and to ensure safe and reliable water quality for desired end use. In this study, a screening level QMRA for a non-membrane based indirect potable reuse (IPR) system utilizing the sequential managed aquifer recharge technology (SMART) concept was conducted. Ambient removals of norovirus, Campylobacter and Cryptosporidium in advanced water treatment (AWT) steps were combined in a probabilistic QMRA utilizing Bayesian networks constructed in Netica. Results revealed that all pathogens complied with disease burden at the 95th percentile, and according to the assumptions taken about pathogen removal, Cryptosporidium was the pathogen with the greatest risk. Through systematic sensitivity analysis, targeted scenario analysis, and backwards inferencing, critical control points for each pathogen were determined, demonstrating the usefulness of Bayesian networks as a diagnostic tool in quantifying risk of water reuse treatment scenarios.
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Affiliation(s)
- Veronika Zhiteneva
- Chair of Urban Water Systems Engineering, Technical University of Munich, Am Coulombwall 3, 85748 Garching, Germany
| | - Guido Carvajal
- Facultad de Ingeniería, Universidad Andrés Bello, Antonio Varas 880, Providencia, Santiago, Chile
| | - Omar Shehata
- Chair of Urban Water Systems Engineering, Technical University of Munich, Am Coulombwall 3, 85748 Garching, Germany
| | - Uwe Hübner
- Chair of Urban Water Systems Engineering, Technical University of Munich, Am Coulombwall 3, 85748 Garching, Germany.
| | - Jörg E Drewes
- Chair of Urban Water Systems Engineering, Technical University of Munich, Am Coulombwall 3, 85748 Garching, Germany
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4
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Fujioka T, Boivin S. Dialysis as a new pre-treatment technique for online bacterial counting. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 714:136768. [PMID: 31982761 DOI: 10.1016/j.scitotenv.2020.136768] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Revised: 12/24/2019] [Accepted: 01/16/2020] [Indexed: 06/10/2023]
Abstract
Real-time bacteriological counting technology is capable of providing an online profile of bacterial removal during the wastewater treatment process, and can enhance the safety of recycled water for potable water reuse. However, autofluorescence emanating from dissolved organic compounds present in treated wastewater interferes with the analysis. In this study, a novel approach is adopted, viz., dialysis treatment for the removal of dissolved interfering substances from treated wastewater, and the efficiency of this treatment protocol is evaluated as a pre-treatment technique for real-time bacteriological counting. Dialysis using membranes having a molecular weight cut-off (MWCO) of 1000 kDa and 6-8 kDa were found to successfully reduce the intensity of autofluorescence emitted from the interfering substances; whereas the courser dialysis membrane having a MWCO of 1000 kDa was found to be more effective in removing the interfering substances. Here we demonstrate for the first time that continuous online dialysis treatment aids in the direct determination of the bacterial counts in ultrafiltration- and membrane bioreactor-treated wastewaters. The results of the study indicate that the dialysis pre-treatment technique is effective for continuously reducing the concentration of interfering substances in treated wastewater, and thus allows for direct online counting of bacteria.
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Affiliation(s)
- Takahiro Fujioka
- Graduate School of Engineering, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan.
| | - Sandrine Boivin
- Graduate School of Engineering, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan
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Horve PF, Lloyd S, Mhuireach GA, Dietz L, Fretz M, MacCrone G, Van Den Wymelenberg K, Ishaq SL. Building upon current knowledge and techniques of indoor microbiology to construct the next era of theory into microorganisms, health, and the built environment. JOURNAL OF EXPOSURE SCIENCE & ENVIRONMENTAL EPIDEMIOLOGY 2020; 30:219-235. [PMID: 31308484 PMCID: PMC7100162 DOI: 10.1038/s41370-019-0157-y] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 06/23/2019] [Accepted: 06/30/2019] [Indexed: 05/06/2023]
Abstract
In the constructed habitat in which we spend up to 90% of our time, architectural design influences occupants' behavioral patterns, interactions with objects, surfaces, rituals, the outside environment, and each other. Within this built environment, human behavior and building design contribute to the accrual and dispersal of microorganisms; it is a collection of fomites that transfer microorganisms; reservoirs that collect biomass; structures that induce human or air movement patterns; and space types that encourage proximity or isolation between humans whose personal microbial clouds disperse cells into buildings. There have been recent calls to incorporate building microbiology into occupant health and exposure research and standards, yet the built environment is largely viewed as a repository for microorganisms which are to be eliminated, instead of a habitat which is inexorably linked to the microbial influences of building inhabitants. Health sectors have re-evaluated the role of microorganisms in health, incorporating microorganisms into prevention and treatment protocols, yet no paradigm shift has occurred with respect to microbiology of the built environment, despite calls to do so. Technological and logistical constraints often preclude our ability to link health outcomes to indoor microbiology, yet sufficient study exists to inform the theory and implementation of the next era of research and intervention in the built environment. This review presents built environment characteristics in relation to human health and disease, explores some of the current experimental strategies and interventions which explore health in the built environment, and discusses an emerging model for fostering indoor microbiology rather than fearing it.
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Affiliation(s)
- Patrick F Horve
- Biology and the Built Environment Center, University of Oregon, Eugene, OR, 97403, USA
| | - Savanna Lloyd
- Biology and the Built Environment Center, University of Oregon, Eugene, OR, 97403, USA
| | - Gwynne A Mhuireach
- Biology and the Built Environment Center, University of Oregon, Eugene, OR, 97403, USA
| | - Leslie Dietz
- Biology and the Built Environment Center, University of Oregon, Eugene, OR, 97403, USA
| | - Mark Fretz
- Institute for Health and the Built Environment, University of Oregon, Portland, OR, 97209, USA
| | - Georgia MacCrone
- Biology and the Built Environment Center, University of Oregon, Eugene, OR, 97403, USA
| | - Kevin Van Den Wymelenberg
- Biology and the Built Environment Center, University of Oregon, Eugene, OR, 97403, USA
- Institute for Health and the Built Environment, University of Oregon, Portland, OR, 97209, USA
| | - Suzanne L Ishaq
- Biology and the Built Environment Center, University of Oregon, Eugene, OR, 97403, USA.
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6
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Hooper J, Funk D, Bell K, Noibi M, Vickstrom K, Schulz C, Machek E, Huang CH. Pilot testing of direct and indirect potable water reuse using multi-stage ozone-biofiltration without reverse osmosis. WATER RESEARCH 2020; 169:115178. [PMID: 31670085 DOI: 10.1016/j.watres.2019.115178] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 09/18/2019] [Accepted: 10/09/2019] [Indexed: 06/10/2023]
Abstract
Pilot testing of direct potable reuse (DPR) using multi-stage ozone and biological filtration as an alternative treatment train without reverse osmosis (RO) was investigated. This study examined four blending ratios of advanced treated reclaimed water from the F. Wayne Hill Water Resources Center (FWH WRC) in Gwinnett County, Georgia, combined with the existing drinking water treatment plant raw water supply, Lake Lanier, for potable water production. Baseline testing with 100 percent (%) Lake Lanier water was initially conducted; followed by testing blends of 15, 25, 50, and 100% reclaimed water from FWH WRC. Finished water quality from the DPR pilot was compared to drinking water standards, and emerging microbial and chemical contaminants were also evaluated. Results were benchmarked against a parallel indirect potable reuse (IPR) pilot receiving 100% of the raw water from Lake Lanier. Finished water quality from the DPR pilot at the 15% blend complied with the United States primary and secondary maximum contaminant levels (MCLs and SMCLs, respectively). However, exceedances of one or more MCLs or SMCLs were observed at higher blends. Importantly, reclaimed water from FWH WRC was of equal or better quality for all microbiological targets tested compared to Lake Lanier, indicating that a DPR scenario could lower acute risks from microbial pathogens compared to current practices. Finished water from the DPR pilot had no detections of microorganisms, even at the 100% FWH WRC effluent blend. Microbiological targets tested included heterotrophic plate counts, total and fecal coliforms, Escherichia coli, somatic and male-specific coliphage, Clostridium perfringens, Enterococci, Legionella, Cryptosporidium, and Giardia. There were water quality challenges, primarily associated with nitrate originating from incomplete denitrification and bromate formation from ozonation at the FWH WRC. These challenges highlight the importance of upstream process monitoring and control at the advanced wastewater treatment facility if DPR is considered. This research demonstrated that ozone with biological filtration could achieve potable water quality criteria, without the use of RO, in cases where nitrate is below the MCL of 10 mg nitrogen per liter and total dissolved solids are below the SMCL of 500 mg per liter.
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Affiliation(s)
- Jennifer Hooper
- CDM Smith, 14432 SE Eastgate Way Suite 100, Bellevue, WA, 98007, USA.
| | - Denise Funk
- Gwinnett County Department of Water Resources, 684 Winder Highway, Lawrenceville, GA, 30045, USA
| | - Kati Bell
- Brown & Caldwell, 220 Athens Way #500, Nashville, TN, 37228, USA
| | - Morayo Noibi
- CDM Smith, 14432 SE Eastgate Way Suite 100, Bellevue, WA, 98007, USA
| | - Kyle Vickstrom
- CDM Smith, 14432 SE Eastgate Way Suite 100, Bellevue, WA, 98007, USA
| | - Chris Schulz
- CDM Smith, 14432 SE Eastgate Way Suite 100, Bellevue, WA, 98007, USA
| | - Eddie Machek
- Georgia Institute of Technology, School of Civil and Environmental Engineering, 200 Bobby Dodd Way, Atlanta, GA, 30332, USA
| | - Ching-Hua Huang
- Georgia Institute of Technology, School of Civil and Environmental Engineering, 200 Bobby Dodd Way, Atlanta, GA, 30332, USA
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7
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Scales PJ, Wijekoon K, Ladwig C, Knight A, Allinson M, Allinson G, Zhang J, Gray S, Packer M, Northcott K, Sheehan D. A critical control point approach to the removal of chemicals of concern from water for reuse. WATER RESEARCH 2019; 160:39-51. [PMID: 31129380 DOI: 10.1016/j.watres.2019.05.035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 05/08/2019] [Accepted: 05/11/2019] [Indexed: 06/09/2023]
Abstract
The reuse of water in a range of potable and non-potable applications is an important factor in the augmentation of water supply and in improving water security and productivity worldwide. A key hindrance to the reuse of water is the cost of compliance testing and process validation associated with ensuring that pathogen and chemicals in the feedwater are removed to a level that ensures no acute or chronic health and/or environmental effects. The critical control point (CCP) approach is well established and widely adopted by water utilities to provide an operational and risk management framework for the removal of pathogens in the treatment system. The application of a CCP approach to barriers in a treatment system for the removal of chemicals is presented. The application exemplar is to a small community wastewater treatment system that aims to produce potable quality water from a secondary treated wastewater effluent, however, the concepts presented are generic. The example used seven treatment barriers, five of which were designed and operated as CCP barriers for pathogens. The work demonstrates a method and risk management framework by which three of the seven barriers could also include a CCP approach for the removal of chemicals. Analogous to a CCP approach for pathogens, the potential is to reduce the use of chemical analysis as a routine determinant of performance criteria. The operational deployment of a CCP approach for chemicals was augmented with the development of a decision tree encompassing the classification of chemicals and the total removal credits across the treatment train in terms of the mechanistic removal of chemicals for each barrier. Validation of the approach is shown for an activated sludge, ozone and reverse osmosis barrier.
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Affiliation(s)
- Peter J Scales
- Particulate Fluids Processing Centre, Department of Chemical Engineering, The University of Melbourne, 3010, Australia.
| | - Kaushalya Wijekoon
- Particulate Fluids Processing Centre, Department of Chemical Engineering, The University of Melbourne, 3010, Australia
| | - Christian Ladwig
- Department of Chemistry, Technical University Munich, Munich, Germany
| | - Adrian Knight
- Particulate Fluids Processing Centre, Department of Chemical Engineering, The University of Melbourne, 3010, Australia
| | - Mayumi Allinson
- Particulate Fluids Processing Centre, Department of Chemical Engineering, The University of Melbourne, 3010, Australia
| | - Graeme Allinson
- Centre for Environmental Sustainability and Remediation, School of Science, RMIT University, Melbourne, 3001, Australia
| | - Jianhua Zhang
- Institute for Sustainable Industries and Liveable Cities, Victoria University, Werribee, 3030, Australia
| | - Stephen Gray
- Institute for Sustainable Industries and Liveable Cities, Victoria University, Werribee, 3030, Australia
| | - Michael Packer
- Australian Antarctic Division, Kingston, 7050, Australia
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8
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Goodwin D, Raffin M, Jeffrey P, Smith HM. Stakeholder evaluations of risk interventions for non-potable recycled water schemes: A case study. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 674:439-450. [PMID: 31005845 DOI: 10.1016/j.scitotenv.2019.04.044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Revised: 04/03/2019] [Accepted: 04/03/2019] [Indexed: 06/09/2023]
Abstract
Non-potable recycled water schemes can benefit sustainable urban water management through reducing demand for drinking water and mitigating environmental loadings through the provision of advanced wastewater treatment. However, scheme feasibility can be diminished by high capital and operating costs which can be elevated by perceptions of health risks and subsequently overly cautious risk reduction measures. Conversely, a failure to anticipate the risk management expectations of stakeholders can undermine scheme feasibility through insufficient demand for recycled water. The aim of this study was to explore how stakeholders' perceptions and preferences for risk management and recycled water end-uses might influence scheme design. Using a case study scheme in London, four risk management intervention scenarios and six alternative end uses were evaluated using a stochastic PROMETHEE-based method that incorporated quantitative microbial risk assessment and stakeholder criteria weights together with an attitudinal survey of stakeholders' risk perceptions. Through pair-wise criteria judgements, results showed that stakeholders prioritised health risk reductions which led to the more conservative management intervention of adding water treatment processes being ranked the highest. In contrast, responses to the attitudinal survey indicated that the stakeholders favoured maintaining the case study's existing levels of risk control but with more stakeholder engagement. The findings highlighted potential benefits of understanding risk perceptions associated with different design options and contrasting these with multi-criteria model results. Extrapolating from these findings, future research could explore potential challenges and benefits of providing flexibility in scheme designs to appeal to a wider range of stakeholder needs as well as being more adaptable to future social, environmental or economic challenges. The study concludes that contemporary risk management guidance would benefit from more explicitly outlining constructive ways to engage stakeholders in scheme evaluation.
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Affiliation(s)
- D Goodwin
- Cranfield Water Science Institute, Cranfield University, Bedfordshire, MK43 0AL, UK
| | - M Raffin
- Thames Water Utilities Ltd, Innovation, Reading STW, Island Road, Reading RG2 0RP, UK
| | - P Jeffrey
- Cranfield Water Science Institute, Cranfield University, Bedfordshire, MK43 0AL, UK
| | - H M Smith
- Cranfield Water Science Institute, Cranfield University, Bedfordshire, MK43 0AL, UK.
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9
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Brouwer AF, Masters NB, Eisenberg JNS. Quantitative Microbial Risk Assessment and Infectious Disease Transmission Modeling of Waterborne Enteric Pathogens. Curr Environ Health Rep 2019; 5:293-304. [PMID: 29679300 DOI: 10.1007/s40572-018-0196-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
PURPOSE OF REVIEW Waterborne enteric pathogens remain a global health threat. Increasingly, quantitative microbial risk assessment (QMRA) and infectious disease transmission modeling (IDTM) are used to assess waterborne pathogen risks and evaluate mitigation. These modeling efforts, however, have largely been conducted independently for different purposes and in different settings. In this review, we examine the settings where each modeling strategy is employed. RECENT FINDINGS QMRA research has focused on food contamination and recreational water in high-income countries (HICs) and drinking water and wastewater in low- and middle-income countries (LMICs). IDTM research has focused on large outbreaks (predominately LMICs) and vaccine-preventable diseases (LMICs and HICs). Human ecology determines the niches that pathogens exploit, leading researchers to focus on different risk assessment research strategies in different settings. To enhance risk modeling, QMRA and IDTM approaches should be integrated to include dynamics of pathogens in the environment and pathogen transmission through populations.
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Affiliation(s)
- Andrew F Brouwer
- Department of Epidemiology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Nina B Masters
- Department of Epidemiology, University of Michigan, Ann Arbor, MI, 48109, USA
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10
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Nappier SP, Soller JA, Eftim SE. Potable Water Reuse: What Are the Microbiological Risks? Curr Environ Health Rep 2019; 5:283-292. [PMID: 29721701 DOI: 10.1007/s40572-018-0195-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
PURPOSE OF REVIEW With the increasing interest in recycling water for potable reuse purposes, it is important to understand the microbial risks associated with potable reuse. This review focuses on potable reuse systems that use high-level treatment and de facto reuse scenarios that include a quantifiable wastewater effluent component. RECENT FINDINGS In this article, we summarize the published human health studies related to potable reuse, including both epidemiology studies and quantitative microbial risk assessments (QMRA). Overall, there have been relatively few health-based studies evaluating the microbial risks associated with potable reuse. Several microbial risk assessments focused on risks associated with unplanned (or de facto) reuse, while others evaluated planned potable reuse, such as indirect potable reuse (IPR) or direct potable reuse (DPR). The reported QMRA-based risks for planned potable reuse varied substantially, indicating there is a need for risk assessors to use consistent input parameters and transparent assumptions, so that risk results are easily translated across studies. However, the current results overall indicate that predicted risks associated with planned potable reuse scenarios may be lower than those for de facto reuse scenarios. Overall, there is a clear need to carefully consider water treatment train choices when wastewater is a component of the drinking water supply (whether de facto, IPR, or DPR). More data from full-scale water treatment facilities would be helpful to quantify levels of viruses in raw sewage and reductions across unit treatment processes for both culturable and molecular detection methods.
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Affiliation(s)
- Sharon P Nappier
- U.S. Environmental Protection Agency, Office of Water, Office of Science and Technology, 1200 Pennsylvania Avenue, NW, Washington, DC, 20460, USA.
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11
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Fujioka T, Makabe R, Mori N, Snyder SA, Leddy M. Assessment of online bacterial particle counts for monitoring the performance of reverse osmosis membrane process in potable reuse. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 667:540-544. [PMID: 30833252 DOI: 10.1016/j.scitotenv.2019.02.339] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Revised: 02/15/2019] [Accepted: 02/21/2019] [Indexed: 06/09/2023]
Abstract
Safety of potable reuse can be enhanced by improved water quality monitoring techniques for assessing water treatment processes. This study evaluated the efficacy of online bacterial counting for continuous monitoring of reverse osmosis (RO) membranes to remove bacteria using real-time bacteriological commercial counters and an on-site pilot-scale RO system. Prior to on-site assessments, the online bacterial counting was verified by comparing the measurement of fluorescent particles in water with flow cytometry. During a seven day pilot test of RO treatment at a water reclamation plant, online bacterial counts in RO permeate were monitored below 15 counts/mL; whereas the bacterial counts in RO feed water were approximately 2500 to 10,000 counts/mL. Removal rates of bacterial counts ranged from 2.6 to 3.1-log (average = 2.9-log) by continuously monitoring bacterial removal. This is greater than a 2-log reduction frequently determined using other water quality surrogates (i.e., electrical conductivity). Overall, the continuous monitoring of bacteria in RO feed and permeate can be implemented without the addition of chemicals to provide near real-time bacterial counts to measure their reduction after RO treatment. This can be developed for continuous performance monitoring of the RO process, providing greater assurance of microbial water quality after RO treatment.
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Affiliation(s)
- Takahiro Fujioka
- Water and Environmental Engineering, Graduate School of Engineering, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan.
| | - Ryo Makabe
- R&D Division, Kyowakiden Industry Co., Ltd., 10-2 Kawaguchi-machi, Nagasaki 852-8108, Japan
| | - Naomichi Mori
- Water Reuse Promotion Center, 4-5 Nihonbashiyokoyamachō, Chuo, Tokyo 103-0003, Japan
| | - Shane A Snyder
- Nanyang Environment & Water Research Institute (NEWRI), Nanyang Technological University (NTU), 1 Cleantech Loop, CleanTech One, Singapore 637141, Singapore; Department of Chemical and Environmental Engineering, University of Arizona, 1133 E. James E. Rogers Way, Harshbarger 108, Tucson, AZ 85721-0011, USA
| | - Menu Leddy
- Orange County Water District, 18700 Ward Street, Fountain Valley, CA 92708, USA; Essential Environmental Engineering Solutions, Huntington Beach, CA 92649, USA
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12
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Hamouda MA, Jin X, Xu H, Chen F. Quantitative microbial risk assessment and its applications in small water systems: A review. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 645:993-1002. [PMID: 30248886 DOI: 10.1016/j.scitotenv.2018.07.228] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Revised: 06/07/2018] [Accepted: 07/16/2018] [Indexed: 06/08/2023]
Abstract
Quantitative microbial risk assessment (QMRA) has been mainstreamed in many large municipal water systems as part of a paradigm shift in the drinking water industry towards water safety planning and risk-based system assessment. Small water systems (SWSs) are generally more vulnerable to typical water system hazards, and consequently have a higher risk of waterborne disease outbreak. In this paper, a review of experiences in implementing QMRA in SWSs helps elaborate the sources of risks and highlights some of the challenges facing SWSs in developed countries. A critical review of the important elements for practical implementation of QMRA was conducted. The investigation focuses on aspects related to challenges in identifying relevant hazards to SWSs to create failure scenarios, acquiring monitoring data for pathogens' concentrations in source water, estimating treatment efficiencies of typical small system technologies, and access to software tools to support successful implementation. The review helped outline ways through which SWSs can overcome the identified challenges in implementing QMRA. An adjusted framework for implementing QMRA for small water systems was formulated and discussed.
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Affiliation(s)
- Mohamed A Hamouda
- Department of Civil and Environmental Engineering, UAE University, P.O. Box 15551, Al Ain, United Arab Emirates; National Water Center, UAE University, P.O. Box 15551, Al Ain, United Arab Emirates.
| | - Xiaohui Jin
- Walkerton Clean Water Centre, 20 Ontario Rd., P.O. Box 160, Walkerton, Ontario N0G 2V0, Canada
| | - Heli Xu
- QuantWave Technologies Inc., 50 Westmount Road North, Waterloo, ON N2L 6N9, Canada
| | - Fei Chen
- QuantWave Technologies Inc., 50 Westmount Road North, Waterloo, ON N2L 6N9, Canada
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Allinson M, Kadokami K, Shiraishi F, Nakajima D, Zhang J, Knight A, Gray SR, Scales PJ, Allinson G. Wastewater recycling in Antarctica: Performance assessment of an advanced water treatment plant in removing trace organic chemicals. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2018; 224:122-129. [PMID: 30036806 DOI: 10.1016/j.jenvman.2018.07.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 07/01/2018] [Accepted: 07/06/2018] [Indexed: 06/08/2023]
Abstract
The Australian Antarctic Division (AAD) operates Australia's Davis Station in the Antarctic. In 2005, Davis Station's wastewater treatment plant failed and since then untreated, macerated effluent has been discharged to the ocean. The objectives of this study were to determine whether an advanced water treatment plant (AWTP) commissioned by the AAD and featuring a multi-barrier process involving ozonation, ceramic microfiltration, biologically activated carbon filtration, reverse osmosis, ultraviolet disinfection and chlorination was capable of producing potable water and a non-toxic brine concentrate that can be discharged with minimal environmental impact. The AWTP was tested using water from a municipal wastewater treatment plant in Tasmania, Australia. We used spot water and passive sampling combined with two multi-residue chromatographic-mass spectrometric methods and a range of recombinant receptor-reporter gene bioassays to screen trace organic chemicals (TrOCs), toxicity and receptor activity in the Feed water, in the environmental discharge (reject water), and product water from the AWTP for six months during 2014-15, and then again for three months in 2016. Across the two surveys we unambiguously detected 109 different TrOCs in the feed water, 39 chemicals in the reject water, and 34 chemicals in the product water. Sample toxicity and receptor activity in the feed water samples was almost totally removed in both testing periods, confirming that the vast majority of the receptor active TrOCs were removed by the treatment process. All the NDMA entering the AWTP in the feed and/or produced in the plant (typically < 50 ng/L), was retained into the reject water with no NDMA observed in the product water. In conclusion, the AWTP was working to design, and releases of TrOCs at the concentrations observed in this study would be unlikely cause adverse effects on populations of aquatic organisms in the receiving environment or users of the potable product water.
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Affiliation(s)
- M Allinson
- Centre for Aquatic Pollution Identification and Management (CAPIM), School of Chemistry, The University of Melbourne, Parkville, Victoria, 3010 Australia
| | - K Kadokami
- Faculty of Environmental Engineering, The University of Kitakyushu, 1-1 Hibikino, Wakamatsu, Kitakyushu, Fukuoka, 808-0135, Japan
| | - F Shiraishi
- Center for Environmental Risk Research, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki, 305-8506, Japan
| | - D Nakajima
- Center for Environmental Risk Research, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki, 305-8506, Japan
| | - J Zhang
- Institute for Sustainability and Innovation, Victoria University, Victoria, Australia
| | - A Knight
- Particulate Fluids Processing Centre, Department of Chemical Engineering, The University of Melbourne, Victoria, 3010, Australia
| | - S R Gray
- Institute for Sustainability and Innovation, Victoria University, Victoria, Australia
| | - P J Scales
- Particulate Fluids Processing Centre, Department of Chemical Engineering, The University of Melbourne, Victoria, 3010, Australia
| | - G Allinson
- Centre for Environmental Sustainability and Remediation (EnSuRe), School of Science, RMIT University, Melbourne, Victoria, 3001, Australia.
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Owusu-Ansah EDGJ, Sampson A, Amponsah SK, Abaidoo RC, Dalsgaard A, Hald T. Probabilistic quantitative microbial risk assessment model of norovirus from wastewater irrigated vegetables in Ghana using genome copies and fecal indicator ratio conversion for estimating exposure dose. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 601-602:1712-1719. [PMID: 28618661 DOI: 10.1016/j.scitotenv.2017.05.168] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2016] [Revised: 05/19/2017] [Accepted: 05/19/2017] [Indexed: 05/22/2023]
Abstract
The need to replace the commonly applied fecal indicator conversions ratio (an assumption of 1:10-5 virus to fecal indicator organism) in Quantitative Microbial Risk Assessment (QMRA) with models based on quantitative data on the virus of interest has gained prominence due to the different physical and environmental factors that might influence the reliability of using indicator organisms in microbial risk assessment. The challenges facing analytical studies on virus enumeration (genome copies or particles) have contributed to the already existing lack of data in QMRA modelling. This study attempts to fit a QMRA model to genome copies of norovirus data. The model estimates the risk of norovirus infection from the intake of vegetables irrigated with wastewater from different sources. The results were compared to the results of a corresponding model using the fecal indicator conversion ratio to estimate the norovirus count. In all scenarios of using different water sources, the application of the fecal indicator conversion ratio underestimated the norovirus disease burden, measured by the Disability Adjusted Life Years (DALYs), when compared to results using the genome copies norovirus data. In some cases the difference was >2 orders of magnitude. All scenarios using genome copies met the 10-4 DALY per person per year for consumption of vegetables irrigated with wastewater, although these results are considered to be highly conservative risk estimates. The fecal indicator conversion ratio model of stream-water and drain-water sources of wastewater achieved the 10-6 DALY per person per year threshold, which tends to indicate an underestimation of health risk when compared to using genome copies for estimating the dose.
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Affiliation(s)
- Emmanuel de-Graft Johnson Owusu-Ansah
- Department of Mathematics, Faculty of Physical and Computational Sciences, SCB-SF 24/B6, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana.
| | - Angelina Sampson
- Department of Chemistry and Biochemistry, South Dakota State University, USA
| | - Samuel K Amponsah
- Department of Mathematics, Faculty of Physical and Computational Sciences, SCB-SF 24/B6, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Robert C Abaidoo
- Department of Theoretical and Applied Biology, Faculty of Bioscience, Biology Block, A 32, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Anders Dalsgaard
- Veterinary Diseases Biology, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Tine Hald
- Genomic Epidemiology and Global Decision Support Initiative, National Food Institute, Soltofts Plads, Building 221 Room 250, Technical University of Denmark, 2800 Kgs Lyngby, Denmark
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Ito T, Kitajima M, Kato T, Ishii S, Segawa T, Okabe S, Sano D. Target virus log 10 reduction values determined for two reclaimed wastewater irrigation scenarios in Japan based on tolerable annual disease burden. WATER RESEARCH 2017; 125:438-448. [PMID: 28898701 DOI: 10.1016/j.watres.2017.08.057] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Revised: 08/23/2017] [Accepted: 08/24/2017] [Indexed: 05/09/2023]
Abstract
Multiple-barriers are widely employed for managing microbial risks in water reuse, in which different types of wastewater treatment units (biological treatment, disinfection, etc.) and health protection measures (use of personal protective gear, vegetable washing, etc.) are combined to achieve a performance target value of log10 reduction (LR) of viruses. The LR virus target value needs to be calculated based on the data obtained from monitoring the viruses of concern and the water reuse scheme in the context of the countries/regions where water reuse is implemented. In this study, we calculated the virus LR target values under two exposure scenarios for reclaimed wastewater irrigation in Japan, using the concentrations of indigenous viruses in untreated wastewater and a defined tolerable annual disease burden (10-4 or 10-6 disability-adjusted life years per person per year (DALYpppy)). Three genogroups of norovirus (norovirus genogroup I (NoV GI), geogroup II (NoV GII), and genogroup IV (NoV GIV)) in untreated wastewater were quantified as model viruses using reverse transcription-microfluidic quantitative PCR, and only NoV GII was present in quantifiable concentration. The probabilistic distribution of NoV GII concentration in untreated wastewater was then estimated from its concentration dataset, and used to calculate the LR target values of NoV GII for wastewater treatment. When an accidental ingestion of reclaimed wastewater by Japanese farmers was assumed, the NoV GII LR target values corresponding to the tolerable annual disease burden of 10-6 DALYpppy were 3.2, 4.4, and 5.7 at 95, 99, and 99.9%tile, respectively. These percentile values, defined as "reliability," represent the cumulative probability of NoV GII concentration distribution in untreated wastewater below the corresponding tolerable annual disease burden after wastewater reclamation. An approximate 1-log10 difference of LR target values was observed between 10-4 and 10-6 DALYpppy. The LR target values were influenced mostly by the change in the logarithmic standard deviation (SD) values of NoV GII concentration in untreated wastewater and the reliability values, which highlights the importance of accurately determining the probabilistic distribution of reference virus concentrations in source water for water reuse.
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Affiliation(s)
- Toshihiro Ito
- Division of Environmental Engineering, Faculty of Engineering, Hokkaido University, North 13, West 8, Kita-ku, Sapporo, Hokkaido 060-8628, Japan
| | - Masaaki Kitajima
- Division of Environmental Engineering, Faculty of Engineering, Hokkaido University, North 13, West 8, Kita-ku, Sapporo, Hokkaido 060-8628, Japan
| | - Tsuyoshi Kato
- Department of Computer Science, Graduate School of Engineering, Gunma University, Tenjinmachi 1-5-1, Kiryu, Gunma 376-8515, Japan
| | - Satoshi Ishii
- Department of Soil, Water, and Climate; BioTechnology Institute, University of Minnesota, 140 Gortner Laboratory of BioChemistry, 14749 Gortner Avenue, St. Paul, MN 55108-1095, USA
| | - Takahiro Segawa
- The Center for Life Science Research, Yamanashi University, 1110, Shimogato, Chuo, Yamanashi, 409-3898, Japan
| | - Satoshi Okabe
- Division of Environmental Engineering, Faculty of Engineering, Hokkaido University, North 13, West 8, Kita-ku, Sapporo, Hokkaido 060-8628, Japan
| | - Daisuke Sano
- Department of Civil and Environmental Engineering, Graduate School of Engineering, Tohoku University, Aoba 6-6-06, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579, Japan.
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16
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Pecson BM, Triolo SC, Olivieri S, Chen EC, Pisarenko AN, Yang CC, Olivieri A, Haas CN, Trussell RS, Trussell RR. Reliability of pathogen control in direct potable reuse: Performance evaluation and QMRA of a full-scale 1 MGD advanced treatment train. WATER RESEARCH 2017; 122:258-268. [PMID: 28609729 DOI: 10.1016/j.watres.2017.06.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Revised: 05/26/2017] [Accepted: 06/05/2017] [Indexed: 05/05/2023]
Abstract
To safely progress toward direct potable reuse (DPR), it is essential to ensure that DPR systems can provide public health protection equivalent to or greater than that of conventional drinking water sources. This study collected data over a one-year period from a full-scale DPR demonstration facility, and used both performance distribution functions (PDFs) and quantitative microbial risk assessment (QMRA) to define and evaluate the reliability of the advanced water treatment facility (AWTF). The AWTF's ability to control enterovirus, Giardia, and Cryptosporidium was characterized using online monitoring of surrogates in a treatment train consisting of ozone, biological activated carbon, microfiltration, reverse osmosis, and ultraviolet light with an advanced oxidation process. This process train was selected to improve reliability by providing redundancy, defined as the provision of treatment beyond the minimum needed to meet regulatory requirements. The PDFs demonstrated treatment that consistently exceeded the 12/10/10-log thresholds for virus, Giardia, and Cryptosporidium, as currently required for potable reuse in California (via groundwater recharge and surface water augmentation). Because no critical process failures impacted pathogen removal performance during the yearlong testing, hypothetical failures were incorporated into the analysis to understand the benefit of treatment redundancy on performance. Each unit process was modeled with a single failure per year lasting four different failure durations: 15 min, 60 min, 8 h, and 24 h. QMRA was used to quantify the impact of failures on pathogen risk. The median annual risk of infection for Cryptosporidium was 4.9 × 10-11 in the absence of failures, and reached a maximum of 1.1 × 10-5 assuming one 24-h failure per process per year. With the inclusion of free chlorine disinfection as part of the treatment process, enterovirus had a median annual infection risk of 1.5 × 10-14 (no failures) and a maximum annual value of 2.1 × 10-5 (assuming one 24-h failure per year). Even with conservative failure assumptions, pathogen risk from this treatment train remains below the risk targets for both the U.S. (10-4 infections/person/year) and the WHO (approximately 10-3 infections/person/year, equivalent to 10-6 DALY/person/year), demonstrating the value of a failure prevention strategy based on treatment redundancy.
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Affiliation(s)
- Brian M Pecson
- Trussell Technologies, 1939 Harrison Street, Suite 600, Oakland, CA 94612, USA.
| | - Sarah C Triolo
- Trussell Technologies, 1939 Harrison Street, Suite 600, Oakland, CA 94612, USA
| | - Simon Olivieri
- ARC Alternatives, Inc., 222 Sutter St, Suite 600, San Francisco, CA 94108, USA
| | - Elise C Chen
- Trussell Technologies, 380 Stevens Avenue, Suite 308, Solana Beach, CA 92075, USA
| | - Aleksey N Pisarenko
- Trussell Technologies, 380 Stevens Avenue, Suite 308, Solana Beach, CA 92075, USA
| | - Chao-Chun Yang
- Trussell Technologies, 232 North Lake Avenue, Suite 300, Pasadena, CA 91101, USA
| | | | - Charles N Haas
- Drexel University, 3141 Chestnut Street, 251 Curtis Hall, Philadelphia, PA 19104, USA
| | - R Shane Trussell
- Trussell Technologies, 380 Stevens Avenue, Suite 308, Solana Beach, CA 92075, USA
| | - R Rhodes Trussell
- Trussell Technologies, 232 North Lake Avenue, Suite 300, Pasadena, CA 91101, USA
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17
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Jahne MA, Schoen ME, Garland JL, Ashbolt NJ. Simulation of enteric pathogen concentrations in locally-collected greywater and wastewater for microbial risk assessments. MICROBIAL RISK ANALYSIS 2017; 5:44-52. [PMID: 30148198 PMCID: PMC6104838 DOI: 10.1016/j.mran.2016.11.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
As decentralized water reuse continues to gain popularity, risk-based treatment guidance is increasingly sought for the protection of public health. However, effort s to evaluate pathogen risks and log-reduction requirements have been hindered by an incomplete understanding of pathogen occurrence and densities in locally-collected wastewaters (i.e., from decentralized collection systems). Of particular interest is the potentially high enteric pathogen concentration in small systems with an active infected excreter, but generally lower frequency of pathogen occurrences in smaller systems compared to those with several hundred contributors. Such variability, coupled with low concentrations in many source streams (e.g., sink, shower/bath, and laundry waters), has limited direct measurement of pathogens. This study presents an approach to modeling pathogen concentrations in variously sized greywater and combined wastewater collection systems based on epidemiological pathogen incidence rates, user population size, and fecal loadings to various residential wastewater sources. Pathogen infections were modeled within various population sizes (5-, 100-, and 1,000-person) for seven reference pathogens (viruses: adenoviruses, Norovirus, and Rotavirus; bacteria: Campylobacter and Salmonella spp.; and protozoa: Cryptosporidium and Giardia spp.) on each day of 10,000 possible years, accounting for intermittent infection and overlap of infection periods within the population. Fecal contamination of fresh greywaters from bathroom sinks, showers/baths, and laundry, as well as combined greywater and local combined wastewater (i.e., including toilets), was modeled based on reported fecal indicators in the various sources. Simulated daily infections and models of fecal contamination were coupled with pathogen shedding characteristics to generate distributions of pathogen densities in the various waters. The predicted frequency of pathogen occurrences in local wastewaters was generally low due to low infection incidence within small cohort groups, but increased with collection scale (population size) and infection incidence rate (e.g., Norovirus). When pathogens did occur, a decrease in concentrations from 5- to 100- and from 100- to 1,000-person systems was observed; nonetheless, overall mean concentrations (i.e., including non-occurrences) remained the same due to the increased number of occurrences. This highlights value of the model for characterizing scaling effects over averaging methods, which overestimate the frequency of pathogen occurrence in small systems while underestimating concentration peaks that likely drive risk periods. Results of this work will inform development of risk-based pathogen reduction requirements for decentralized water reuse.
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Affiliation(s)
- Michael A. Jahne
- U.S. Environmental Protection Agency, 26 W. Martin Luther King Dr., Cincinnati OH 45268, United States
| | - Mary E. Schoen
- Soller Environmental, 3022 King St., Berkeley, CA 94703, United States
| | - Jay L. Garland
- U.S. Environmental Protection Agency, 26 W. Martin Luther King Dr., Cincinnati OH 45268, United States
| | - Nicholas J. Ashbolt
- University of Alberta, Rm 3-57D South Academic Building, Edmonton, AB T6G 2G7, Canada
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18
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Kobayashi N, Oshiki M, Ito T, Segawa T, Hatamoto M, Kato T, Yamaguchi T, Kubota K, Takahashi M, Iguchi A, Tagawa T, Okubo T, Uemura S, Harada H, Motoyama T, Araki N, Sano D. Removal of human pathogenic viruses in a down-flow hanging sponge (DHS) reactor treating municipal wastewater and health risks associated with utilization of the effluent for agricultural irrigation. WATER RESEARCH 2017; 110:389-398. [PMID: 28038763 DOI: 10.1016/j.watres.2016.10.054] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2016] [Revised: 10/18/2016] [Accepted: 10/21/2016] [Indexed: 06/06/2023]
Abstract
A down-flow hanging sponge (DHS) reactor has been developed as a cost-effective wastewater treatment system that is adaptable to local conditions in low-income countries. A pilot-scale DHS reactor previously demonstrated stable reduction efficiencies for chemical oxygen demand (COD) and ammonium nitrogen over a year at ambient temperature, but the pathogen reduction efficiency of the DHS reactor has yet to be investigated. In the present study, the reduction efficiency of a pilot-scale DHS reactor fed with municipal wastewater was investigated for 10 types of human pathogenic viruses (norovirus GI, GII and GIV, aichivirus, astrovirus, enterovirus, hepatitis A and E viruses, rotavirus, and sapovirus). DHS influent and effluent were collected weekly or biweekly for 337 days, and concentrations of viral genomes were determined by microfluidic quantitative PCR. Aichivirus, norovirus GI and GII, enterovirus, and sapovirus were frequently detected in DHS influent, and the log10 reduction (LR) of these viruses ranged from 1.5 to 3.7. The LR values for aichivirus and norovirus GII were also calculated using a Bayesian estimation model, and the average LR (±standard deviation) values for aichivirus and norovirus GII were estimated to be 1.4 (±1.5) and 1.8 (±2.5), respectively. Quantitative microbial risk assessment was conducted to calculate a threshold reduction level for norovirus GII that would be required for the use of DHS effluent for agricultural irrigation, and it was found that LRs of 2.6 and 3.7 for norovirus GII in the DHS effluent were required in order to not exceed the tolerable burden of disease at 10-4 and 10-6 disability-adjusted life years loss per person per year, respectively, for 95% of the exposed population during wastewater reuse for irrigation.
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Affiliation(s)
- Naohiro Kobayashi
- Department of Civil Engineering, National Institute of Technology, Nagaoka College, 888 Nishikatakaimachi, Nagaoka, Niigata, 940-0834, Japan
| | - Mamoru Oshiki
- Department of Civil Engineering, National Institute of Technology, Nagaoka College, 888 Nishikatakaimachi, Nagaoka, Niigata, 940-0834, Japan.
| | - Toshihiro Ito
- Division of Environmental Engineering, Faculty of Engineering, Hokkaido University, North 13, West-8, Sapporo, Hokkaido, 060-8628, Japan
| | - Takahiro Segawa
- Transdisciplinary Research Integration Center, 4-3-13 Toranomon, Minato-ku, Tokyo, Japan; Transdisciplinary Research Integration Center, National Institute of Polar Research, Japan
| | - Masashi Hatamoto
- Department of Environmental Systems Engineering, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka, Niigata, 940-2188, Japan
| | - Tsuyoshi Kato
- Department of Computer Science, Gunma University, 3-39-22 Syowamachi, Maebashi, Gunma, 371-8511, Japan
| | - Takashi Yamaguchi
- Department of Science of Technology Innovation, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka, Niigata, 940-2188, Japan
| | - Kengo Kubota
- Department of Civil and Environmental Engineering, Tohoku University, 6-6-06 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi, 980-8579, Japan
| | - Masanobu Takahashi
- New Industry Creation Hatchery Center (NICHe), Tohoku University, 6-6-06 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi, 980-8579, Japan
| | - Akinori Iguchi
- Faculty of Applied Life Sciences, Niigata University of Pharmacy and Applied Life Sciences, 265-1 Higashiyama, Akiba-ku, Niigata, 956-0841, Japan
| | - Tadashi Tagawa
- Department of Civil Engineering, National Institute of Technology, Kagawa College, 355 Chokushicho, Takamatsu, Kagawa, 761-8058, Japan
| | - Tsutomu Okubo
- Department of Civil Engineering, National Institute of Technology, Kisarazu College, 2-11-1 Kiyomidaihigashi, Kisarazu, Chiba, 292-0041, Japan
| | - Shigeki Uemura
- Department of Civil Engineering, National Institute of Technology, Kisarazu College, 2-11-1 Kiyomidaihigashi, Kisarazu, Chiba, 292-0041, Japan
| | - Hideki Harada
- New Industry Creation Hatchery Center (NICHe), Tohoku University, 6-6-06 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi, 980-8579, Japan
| | - Toshiki Motoyama
- Department of Civil Engineering, National Institute of Technology, Nagaoka College, 888 Nishikatakaimachi, Nagaoka, Niigata, 940-0834, Japan
| | - Nobuo Araki
- Department of Civil Engineering, National Institute of Technology, Nagaoka College, 888 Nishikatakaimachi, Nagaoka, Niigata, 940-0834, Japan
| | - Daisuke Sano
- Division of Environmental Engineering, Faculty of Engineering, Hokkaido University, North 13, West-8, Sapporo, Hokkaido, 060-8628, Japan
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20
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Van Abel N, Schoen ME, Kissel JC, Meschke JS. Comparison of Risk Predicted by Multiple Norovirus Dose-Response Models and Implications for Quantitative Microbial Risk Assessment. RISK ANALYSIS : AN OFFICIAL PUBLICATION OF THE SOCIETY FOR RISK ANALYSIS 2017; 37:245-264. [PMID: 27285380 DOI: 10.1111/risa.12616] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Revised: 02/26/2016] [Accepted: 03/01/2016] [Indexed: 05/06/2023]
Abstract
The application of quantitative microbial risk assessments (QMRAs) to understand and mitigate risks associated with norovirus is increasingly common as there is a high frequency of outbreaks worldwide. A key component of QMRA is the dose-response analysis, which is the mathematical characterization of the association between dose and outcome. For Norovirus, multiple dose-response models are available that assume either a disaggregated or an aggregated intake dose. This work reviewed the dose-response models currently used in QMRA, and compared predicted risks from waterborne exposures (recreational and drinking) using all available dose-response models. The results found that the majority of published QMRAs of norovirus use the 1 F1 hypergeometric dose-response model with α = 0.04, β = 0.055. This dose-response model predicted relatively high risk estimates compared to other dose-response models for doses in the range of 1-1,000 genomic equivalent copies. The difference in predicted risk among dose-response models was largest for small doses, which has implications for drinking water QMRAs where the concentration of norovirus is low. Based on the review, a set of best practices was proposed to encourage the careful consideration and reporting of important assumptions in the selection and use of dose-response models in QMRA of norovirus. Finally, in the absence of one best norovirus dose-response model, multiple models should be used to provide a range of predicted outcomes for probability of infection.
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Affiliation(s)
- Nicole Van Abel
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA, USA
| | - Mary E Schoen
- Soller Environmental, Berkeley, Inc., Berkeley, CA, USA
| | - John C Kissel
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA, USA
| | - J Scott Meschke
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA, USA
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21
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Leow A, Burkhardt J, Platten WE, Zimmerman B, Brinkman NE, Turner A, Murray R, Sorial G, Garland J. Application of the CANARY event detection software for real-time performance monitoring of decentralized water reuse systems. ENVIRONMENTAL SCIENCE : WATER RESEARCH & TECHNOLOGY 2017; 3:224-234. [PMID: 33425368 PMCID: PMC7787991 DOI: 10.1039/c6ew00226a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Real-time monitoring of water reuse systems ensures the production of high quality water to protect human health at the point-of-use. In this study, several online real-time sensors were utilized to monitor effluent from a wastewater fed laboratory-scale membrane bioreactor (MBR) under natural and simulated failure conditions. These simulated failures included adding reactor mixed liquor to emulate a membrane breach, and spiking MS2 bacteriophage into the reactor to create a high viral load, which might be observed during an outbreak. The CANARY event detection software was used to analyze sensor data and report changes in water quality that might be indicative of poor system behavior. During simulated failure conditions, CANARY reported 20 alarms, accurately detecting each failure. During natural operating conditions, 219 alarms were produced and 189 were attributed to known events (e.g., system and sensor maintenance). The remaining alarms (23) during natural operating conditions were considered to have an unknown cause. However, 13 of those had signal deviations similar to known events, but could not be definitively linked to a source. The results of this study suggest that real-time monitoring in conjunction with CANARY analysis may be useful as an early warning system for monitoring the effluent of water reuse systems, and may help to quickly identify treatment malfunctions or other abnormal conditions.
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Affiliation(s)
- Aaron Leow
- University of Cincinnati, Department of Biomedical, Chemical, and Environmental Engineering, 2901 Woodside Drive, Cincinnati, OH 45221, USA
| | - Jonathan Burkhardt
- National Homeland Security Research Center, United States Environmental Protection Agency, 26 W. Martin Luther King Dr., Cincinnati, OH 45268, USA
| | - William E Platten
- Pegasus Technical Services, Inc., 46 E. Hollister St., Cincinnati, OH 45219, USA
| | - Brian Zimmerman
- Student Services Contractor, United States Environmental Protection Agency, 26 W. Martin Luther King Dr., Cincinnati, OH 45268, USA
| | - Nichole E Brinkman
- Systems Exposure Division, National Exposure Research Laboratory, United States Environmental Protection Agency, 26 W. Martin Luther King Dr., MS 587 Cincinnati, OH 45268, USA
| | - Anne Turner
- Student Services Contractor, United States Environmental Protection Agency, 26 W. Martin Luther King Dr., Cincinnati, OH 45268, USA
| | - Regan Murray
- National Homeland Security Research Center, United States Environmental Protection Agency, 26 W. Martin Luther King Dr., Cincinnati, OH 45268, USA
| | - George Sorial
- University of Cincinnati, Department of Biomedical, Chemical, and Environmental Engineering, 2901 Woodside Drive, Cincinnati, OH 45221, USA
| | - Jay Garland
- Systems Exposure Division, National Exposure Research Laboratory, United States Environmental Protection Agency, 26 W. Martin Luther King Dr., MS 587 Cincinnati, OH 45268, USA
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22
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Verbyla ME, Symonds EM, Kafle RC, Cairns MR, Iriarte M, Mercado Guzmán A, Coronado O, Breitbart M, Ledo C, Mihelcic JR. Managing Microbial Risks from Indirect Wastewater Reuse for Irrigation in Urbanizing Watersheds. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:6803-13. [PMID: 26992352 DOI: 10.1021/acs.est.5b05398] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Limited supply of clean water in urbanizing watersheds creates challenges for safely sustaining irrigated agriculture and global food security. On-farm interventions, such as riverbank filtration (RBF), are used in developing countries to treat irrigation water from rivers with extensive fecal contamination. Using a Bayesian approach incorporating ethnographic data and pathogen measurements, quantitative microbial risk assessment (QMRA) methods were employed to assess the impact of RBF on consumer health burdens for Giardia, Cryptosporidium, rotavirus, norovirus, and adenovirus infections resulting from indirect wastewater reuse, with lettuce irrigation in Bolivia as a model system. Concentrations of the microbial source tracking markers pepper mild mottle virus and HF183 Bacteroides were respectively 2.9 and 5.5 log10 units lower in RBF-treated water than in the river water. Consumption of lettuce irrigated with river water caused an estimated median health burden that represents 37% of Bolivia's overall diarrheal disease burden, but RBF resulted in an estimated health burden that is only 1.1% of this overall diarrheal disease burden. Variability and uncertainty associated with environmental and cultural factors affecting exposure correlated more with QMRA-predicted health outcomes than factors related to disease vulnerability. Policies governing simple on-farm interventions like RBF can be intermediary solutions for communities in urbanizing watersheds that currently lack wastewater treatment.
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Affiliation(s)
- Matthew E Verbyla
- Department of Civil & Environmental Engineering, University of South Florida , 4202 E. Fowler Avenue, Tampa, Florida 33620, United States
| | - Erin M Symonds
- College of Marine Science, University of South Florida , 140 Seventh Avenue South, St. Petersburg, Florida 33701, United States
| | - Ram C Kafle
- Department of Mathematics & Statistics, University of South Florida , 4202 E. Fowler Avenue, Tampa, Florida 33620, United States
| | - Maryann R Cairns
- Department of Anthropology, University of South Florida , 4202 E. Fowler Avenue, Tampa, Florida 33620, United States
| | - Mercedes Iriarte
- Center for Water and Environmental Sanitation (Centro de Aguas y Saneamiento Ambiental, CASA), Universidad Mayor de San Simon , Cochabamba, Bolivia
| | - Alvaro Mercado Guzmán
- Center for Water and Environmental Sanitation (Centro de Aguas y Saneamiento Ambiental, CASA), Universidad Mayor de San Simon , Cochabamba, Bolivia
| | - Olver Coronado
- Center for Water and Environmental Sanitation (Centro de Aguas y Saneamiento Ambiental, CASA), Universidad Mayor de San Simon , Cochabamba, Bolivia
| | - Mya Breitbart
- College of Marine Science, University of South Florida , 140 Seventh Avenue South, St. Petersburg, Florida 33701, United States
| | - Carmen Ledo
- Center for Urban Planning and Management (Centro de Planificación y Gestión, CePlaG), Universidad Mayor de San Simon , Cochabamba, Bolivia
| | - James R Mihelcic
- Department of Civil & Environmental Engineering, University of South Florida , 4202 E. Fowler Avenue, Tampa, Florida 33620, United States
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23
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Beaudequin D, Harden F, Roiko A, Mengersen K. Utility of Bayesian networks in QMRA-based evaluation of risk reduction options for recycled water. THE SCIENCE OF THE TOTAL ENVIRONMENT 2016; 541:1393-1409. [PMID: 26479913 DOI: 10.1016/j.scitotenv.2015.10.030] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Revised: 10/07/2015] [Accepted: 10/07/2015] [Indexed: 06/05/2023]
Abstract
BACKGROUND Quantitative microbial risk assessment (QMRA), the current method of choice for evaluating human health risks associated with disease-causing microorganisms, is often constrained by issues such as availability of required data, and inability to incorporate the multitude of factors influencing risk. Bayesian networks (BNs), with their ability to handle data paucity, combine quantitative and qualitative information including expert opinions, and ability to offer a systems approach to characterisation of complexity, are increasingly recognised as a powerful, flexible tool that overcomes these limitations. OBJECTIVES We present a QMRA expressed as a Bayesian network (BN) in a wastewater reuse context, with the objective of demonstrating the utility of the BN method in health risk assessments, particularly for evaluating a range of exposure and risk mitigation scenarios. As a case study, we examine the risk of norovirus infection associated with wastewater-irrigated lettuce. METHODS A Bayesian network was developed following a QMRA approach, using published data, and reviewed by domain experts using a participatory process. DISCUSSION Employment of a BN facilitated rapid scenario evaluations, risk minimisation, and predictive comparisons. The BN supported exploration of conditions required for optimal outcomes, as well as investigation of the effect on the reporting nodes of changes in 'upstream' conditions. A significant finding was the indication that if maximum post-treatment risk mitigation measures were implemented, there was a high probability (0.84) of a low risk of infection regardless of fluctuations in other variables, including norovirus concentration in treated wastewater. CONCLUSION BNs are useful in situations where insufficient empirical data exist to satisfy QMRA requirements and they are exceptionally suited to the integration of risk assessment and risk management in the QMRA context. They allow a comprehensive visual appraisal of major influences in exposure pathways, and rapid interactive risk assessment in multifaceted water reuse scenarios.
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Affiliation(s)
- Denise Beaudequin
- Faculty of Health, Queensland University of Technology, Gardens Point Campus, 2 George Street, Brisbane, Queensland 4000, Australia; Institute of Health and Biomedical Innovation (IHBI), Queensland University of Technology, 60 Musk Avenue, Kelvin Grove, Queensland 4059, Australia.
| | - Fiona Harden
- Faculty of Health, Queensland University of Technology, Gardens Point Campus, 2 George Street, Brisbane, Queensland 4000, Australia; Institute of Health and Biomedical Innovation (IHBI), Queensland University of Technology, 60 Musk Avenue, Kelvin Grove, Queensland 4059, Australia.
| | - Anne Roiko
- School of Medicine, Griffith University, Gold Coast Campus, Parklands Drive, Southport, Queensland 4222, Australia; Smartwater Research Centre, Griffith University, Gold Coast Campus, Edmund Rice Dr, Southport, Queensland 4215, Australia.
| | - Kerrie Mengersen
- Science and Engineering Faculty, Queensland University of Technology, Gardens Point Campus, 2 George Street, Brisbane, Queensland 4000, Australia; Institute for Future Environments (IFE), Queensland University of Technology, Gardens Point Campus, 2 George Street, Brisbane, Queensland 4000, Australia.
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24
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Lim KY, Hamilton AJ, Jiang SC. Assessment of public health risk associated with viral contamination in harvested urban stormwater for domestic applications. THE SCIENCE OF THE TOTAL ENVIRONMENT 2015; 523:95-108. [PMID: 25863500 DOI: 10.1016/j.scitotenv.2015.03.077] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Revised: 03/18/2015] [Accepted: 03/18/2015] [Indexed: 04/14/2023]
Abstract
Capturing stormwater is becoming a new standard for sustainable urban stormwater management, which can be used to supplement water supply portfolios in water-stressed cities. The key advantage of harvesting stormwater is to use low impact development (LID) systems for treatment to meet water quality requirement for non-potable uses. However, the lack of scientific studies to validate the safety of such practice has limited its adoption. Microbial hazards in stormwater, especially human viruses, represent the primary public health threat. Using adenovirus and norovirus as target pathogens, we investigated the viral health risk associated with a generic scenario of urban stormwater harvesting practice and its application for three non-potable uses: 1) toilet flushing, 2) showering, and 3) food-crop irrigation. The Quantitative Microbial Risk Assessment (QMRA) results showed that food-crop irrigation has the highest annual viral infection risk (median range: 6.8×10(-4)-9.7×10(-1) per-person-per-year or pppy), followed by showering (3.6×10(-7)-4.3×10(-2)pppy), and toilet flushing (1.1×10(-7)-1.3×10(-4)pppy). Disease burden of each stormwater use was ranked in the same order as its viral infection risk: food-crop irrigation>showering>toilet flushing. The median and 95th percentile risk values of toilet-flushing using treated stormwater are below U.S. EPA annual risk benchmark of ≤10(-4)pppy, whereas the disease burdens of both toilet-flushing and showering are within the WHO recommended disease burdens of ≤10(-6)DALYspppy. However, the acceptability of showering risk interpreted based on the U.S. EPA and WHO benchmarks is in disagreement. These results confirm the safety of stormwater application in toilet flushing, but call for further research to fill the data gaps in risk modeling as well as risk benchmarks.
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Affiliation(s)
- Keah-Ying Lim
- Department of Civil and Environmental Engineering, University of California, Irvine, CA 92617-2175, USA
| | - Andrew J Hamilton
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Dookie Campus, Currawa, VIC 3647, Australia; Federation University Australia, Mt Helen Campus, VIC 3353, Australia
| | - Sunny C Jiang
- Department of Civil and Environmental Engineering, University of California, Irvine, CA 92617-2175, USA.
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25
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Symonds EM, Verbyla ME, Lukasik JO, Kafle RC, Breitbart M, Mihelcic JR. A case study of enteric virus removal and insights into the associated risk of water reuse for two wastewater treatment pond systems in Bolivia. WATER RESEARCH 2014; 65:257-70. [PMID: 25129566 DOI: 10.1016/j.watres.2014.07.032] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Revised: 07/15/2014] [Accepted: 07/23/2014] [Indexed: 05/20/2023]
Abstract
Wastewater treatment ponds (WTP) are one of the most widespread treatment technologies in the world; however, the mechanisms and extent of enteric virus removal in these systems are poorly understood. Two WTP systems in Bolivia, with similar overall hydraulic retention times but different first stages of treatment, were analyzed for enteric virus removal. One system consisted of a facultative pond followed by two maturation ponds (three-pond system) and the other consisted of an upflow anaerobic sludge blanket (UASB) reactor followed by two maturation (polishing) ponds (UASB-pond system). Quantitative polymerase chain reaction with reverse transcription (RT-qPCR) was used to measure concentrations of norovirus, rotavirus, and pepper mild mottle virus, while cell culture methods were used to measure concentrations of culturable enteroviruses (EV). Limited virus removal was observed with RT-qPCR in either system; however, the three-pond system removed culturable EV with greater efficiency than the UASB-pond system. The majority of viruses were not associated with particles and only a small proportion was associated with particles larger than 180 μm; thus, it is unlikely that sedimentation is a major mechanism of virus removal. High concentrations of viruses were associated with particles between 0.45 and 180 μm in the UASB reactor effluent, but not in the facultative pond effluent. The association of viruses with this size class of particles may explain why only minimal virus removal was observed in the UASB-pond system. Quantitative microbial risk assessment of the treated effluent for reuse for restricted irrigation indicated that the three-pond system effluent requires an additional 1- to 2-log10 reduction of viruses to achieve the WHO health target of <10(-4) disability-adjusted life years (DALYs) lost per person per year; however, the UASB-pond system effluent may require an additional 2.5- to 4.5-log10 reduction of viruses.
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Affiliation(s)
- E M Symonds
- University of South Florida, College of Marine Science, 140 7th Avenue South, St. Petersburg, FL, USA.
| | - M E Verbyla
- University of South Florida, Department of Civil & Environmental Engineering, 4202 E. Fowler Avenue, Tampa, FL, USA.
| | - J O Lukasik
- Biological Consulting Services of North Central Florida, Inc., 4609-A NW 6th Street, Gainesville, FL, USA.
| | - R C Kafle
- University of South Florida, Department of Mathematics and Statistics, 4202 E. Fowler Avenue, Tampa, FL, USA.
| | - M Breitbart
- University of South Florida, College of Marine Science, 140 7th Avenue South, St. Petersburg, FL, USA.
| | - J R Mihelcic
- University of South Florida, Department of Civil & Environmental Engineering, 4202 E. Fowler Avenue, Tampa, FL, USA.
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26
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Harder R, Heimersson S, Svanström M, Peters GM. Including pathogen risk in life cycle assessment of wastewater management. 1. Estimating the burden of disease associated with pathogens. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2014; 48:9438-9445. [PMID: 25058492 DOI: 10.1021/es501480q] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The environmental performance of wastewater and sewage sludge management is commonly assessed using life cycle assessment (LCA), whereas pathogen risk is evaluated with quantitative microbial risk assessment (QMRA). This study explored the application of QMRA methodology with intent to include pathogen risk in LCA and facilitate a comparison with other potential impacts on human health considered in LCA. Pathogen risk was estimated for a model wastewater treatment system (WWTS) located in an industrialized country and consisting of primary, secondary, and tertiary wastewater treatment, anaerobic sludge digestion, and land application of sewage sludge. The estimation was based on eight previous QMRA studies as well as parameter values taken from the literature. A total pathogen risk (expressed as burden of disease) on the order of 0.2-9 disability-adjusted life years (DALY) per year of operation was estimated for the model WWTS serving 28,600 persons and for the pathogens and exposure pathways included in this study. The comparison of pathogen risk with other potential impacts on human health considered in LCA is detailed in part 2 of this article series.
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Affiliation(s)
- Robin Harder
- Chemical Environmental Science, Department of Chemical and Biological Engineering, Chalmers University of Technology , Gothenburg, 412 96 Sweden
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27
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Maimon A, Friedler E, Gross A. Parameters affecting greywater quality and its safety for reuse. THE SCIENCE OF THE TOTAL ENVIRONMENT 2014; 487:20-5. [PMID: 24751591 DOI: 10.1016/j.scitotenv.2014.03.133] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Revised: 03/27/2014] [Accepted: 03/27/2014] [Indexed: 05/26/2023]
Abstract
Reusing greywater (GW) for on-site irrigation is becoming a common practice worldwide. Alongside its benefits, GW reuse might pose health and environmental risks. The current study assesses the risks associated with on-site GW reuse and the main factors affecting them. GW from 34 households in Israel was analyzed for physicochemical parameters, Escherichia coli (as an indicator for rotavirus), Pseudomonas aeruginosa and Staphylococcus aureus. Each participating household filled out a questionnaire about their GW sources, treatment and usages. Quantitative microbial risk assessment (QMRA) was performed based on the measured microbial quality, and on exposure scenarios derived from the questionnaires and literature data. The type of treatment was found to have a significant effect on the quality of the treated GW. The average E. coli counts in GW (which exclude kitchen effluent) treated by professionally-designed system resulted in acceptable risk under all exposure scenarios while the risk from inadequately-treated GW was above the accepted level as set by the WHO. In conclusion, safe GW reuse requires a suitable and well-designed treatment system. A risk-assessment approach should be used to adjust the current regulations/guidelines and to assess the performance of GW treatment and reuse systems.
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Affiliation(s)
- Adi Maimon
- Albert Katz International School for Desert Studies, Department of Environmental Hydrology and Microbiology, Zuckerberg Institute for Water Research, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus, 84990, Israel
| | - Eran Friedler
- Faculty of Civil & Environmental Engineering, Technion - Israel Inst. of Technology, Technion, Haifa 3200, Israel
| | - Amit Gross
- Albert Katz International School for Desert Studies, Department of Environmental Hydrology and Microbiology, Zuckerberg Institute for Water Research, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus, 84990, Israel.
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28
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Barker SF, Amoah P, Drechsel P. A probabilistic model of gastroenteritis risks associated with consumption of street food salads in Kumasi, Ghana: evaluation of methods to estimate pathogen dose from water, produce or food quality. THE SCIENCE OF THE TOTAL ENVIRONMENT 2014; 487:130-142. [PMID: 24784738 DOI: 10.1016/j.scitotenv.2014.03.108] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2013] [Revised: 03/22/2014] [Accepted: 03/22/2014] [Indexed: 06/03/2023]
Abstract
With a rapidly growing urban population in Kumasi, Ghana, the consumption of street food is increasing. Raw salads, which often accompany street food dishes, are typically composed of perishable vegetables that are grown in close proximity to the city using poor quality water for irrigation. This study assessed the risk of gastroenteritis illness (caused by rotavirus, norovirus and Ascaris lumbricoides) associated with the consumption of street food salads using Quantitative Microbial Risk Assessment (QMRA). Three different risk assessment models were constructed, based on availability of microbial concentrations: 1) Water - starting from irrigation water quality, 2) Produce - starting from the quality of produce at market, and 3) Street - using microbial quality of street food salad. In the absence of viral concentrations, published ratios between faecal coliforms and viruses were used to estimate the quality of water, produce and salad, and annual disease burdens were determined. Rotavirus dominated the estimates of annual disease burden (~10(-3)Disability Adjusted Life Years per person per year (DALYs pppy)), although norovirus also exceeded the 10(-4)DALY threshold for both Produce and Street models. The Water model ignored other on-farm and post-harvest sources of contamination and consistently produced lower estimates of risk; it likely underestimates disease burden and therefore is not recommended. Required log reductions of up to 5.3 (95th percentile) for rotavirus were estimated for the Street model, demonstrating that significant interventions are required to protect the health and safety of street food consumers in Kumasi. Estimates of virus concentrations were a significant source of model uncertainty and more data on pathogen concentrations is needed to refine QMRA estimates of disease burden.
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Affiliation(s)
- S Fiona Barker
- Department of Resource Management and Geography, The University of Melbourne, Parkville, VIC 3010, Australia.
| | - Philip Amoah
- International Water Management Institute (IWMI) West Africa Office, PMB CT 112 Accra, Ghana
| | - Pay Drechsel
- International Water Management Institute (IWMI), P.O.B. 2075, Colombo, Sri Lanka
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29
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Barker SF. Risk of norovirus gastroenteritis from consumption of vegetables irrigated with highly treated municipal wastewater--evaluation of methods to estimate sewage quality. RISK ANALYSIS : AN OFFICIAL PUBLICATION OF THE SOCIETY FOR RISK ANALYSIS 2014; 34:803-817. [PMID: 24286258 DOI: 10.1111/risa.12138] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Quantitative microbial risk assessment was used to assess the risk of norovirus gastroenteritis associated with consumption of raw vegetables irrigated with highly treated municipal wastewater, using Melbourne, Australia as an example. In the absence of local norovirus concentrations, three methods were developed: (1) published concentrations of norovirus in raw sewage, (2) an epidemiological method using Melbourne prevalence of norovirus, and (3) an adjustment of method 1 to account for prevalence of norovirus. The methods produced highly variable results with estimates of norovirus concentrations in raw sewage ranging from 10(4) per milliliter to 10(7) per milliliter and treated effluent from 1 × 10(-3) per milliliter to 3 per milliliter (95th percentiles). Annual disease burden was very low using method 1, from 4 to 5 log10 disability adjusted life years (DALYs) below the 10(-6) threshold (0.005-0.1 illnesses per year). Results of method 2 were higher, with some scenarios exceeding the threshold by up to 2 log10 DALYs (up to 95,000 illnesses per year). Method 3, thought to be most representative of Melbourne conditions, predicted annual disease burdens >2 log10 DALYs lower than the threshold (∼ 4 additional cases per year). Sensitivity analyses demonstrated that input parameters used to estimate norovirus concentration accounted for much of the model output variability. This model, while constrained by a lack of knowledge of sewage concentrations, used the best available information and sound logic. Results suggest that current wastewater reuse behaviors in Melbourne are unlikely to cause norovirus risks in excess of the annual DALY health target.
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30
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Mok HF, Barker SF, Hamilton AJ. A probabilistic quantitative microbial risk assessment model of norovirus disease burden from wastewater irrigation of vegetables in Shepparton, Australia. WATER RESEARCH 2014; 54:347-62. [PMID: 24594660 DOI: 10.1016/j.watres.2014.01.060] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Revised: 01/24/2014] [Accepted: 01/26/2014] [Indexed: 05/22/2023]
Abstract
Wastewater can be an important resource for water-scarce regions of the world, but a major barrier to its use is the associated health risk. Quantitative microbial risk assessment (QMRA) is a probabilistic modeling technique used to determine the health risks from wastewater reuse, but only a handful of QMRA studies have examined the norovirus health risks from consumption of vegetables irrigated with human wastewater, even though norovirus is a, if not the most, significant microbial cause of diarrheal disease world-wide. Furthermore, the majority of these studies have focused only on risks from lettuce consumption. To meet the knowledge gap in health risks for other vegetables, a QMRA model was constructed for agricultural wastewater irrigation in the regional city of Shepparton, Australia, using fecal shedding rates to estimate norovirus concentration in raw sewage. Annual norovirus disease burden was estimated for the consumption of lettuce, broccoli, cabbage, Asian vegetables, and cucumber after irrigation with treated wastewater. Results indicate that the waste stabilization pond treatment did not have sufficient virus removal to meet the World Health Organization (WHO) threshold for acceptable level of risk for wastewater reuse, but addition of disinfection treatments provided acceptable results for consumption of cucumber and broccoli. This is the first QMRA study to incorporate virus accumulation from previous wastewater irrigation events.
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Affiliation(s)
- Hoi-Fei Mok
- Department of Agriculture and Food Systems, Melbourne School of Land and Environment, University of Melbourne, Parkville, VIC 3010, Australia
| | - S Fiona Barker
- Department of Resource Management and Geography, Melbourne School of Land and Environment, University of Melbourne, Parkville, VIC 3010, Australia
| | - Andrew J Hamilton
- Department of Agriculture and Food Systems, Melbourne School of Land and Environment, University of Melbourne, Parkville, VIC 3010, Australia.
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