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Reynaert E, Sylvestre É, Morgenroth E, Julian TR. Greywater recycling for diverse collection scales and appliances: Enteric pathogen log-removal targets and treatment trains. WATER RESEARCH 2024; 264:122216. [PMID: 39146850 DOI: 10.1016/j.watres.2024.122216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2024] [Revised: 07/29/2024] [Accepted: 08/03/2024] [Indexed: 08/17/2024]
Abstract
In light of increasingly diverse greywater reuse applications, this study proposes risk-based log-removal targets (LRTs) to aid the selection of treatment trains for greywater recycling at different collection scales, including appliance-scale reuse of individual greywater streams. An epidemiology-based model was used to simulate the concentrations of prevalent and treatment-resistant reference pathogens (protozoa: Giardia and Cryptosporidium spp., bacteria: Salmonella and Campylobacter spp., viruses: rotavirus, norovirus, adenovirus, and Coxsackievirus B5) in the greywater streams for collection scales of 5-, 100-, and a 1000-people. Using quantitative microbial risk assessment (QMRA), we calculated LRTs to meet a health benchmark of 10-4 infections per person per year over 10'000 Monte Carlo iterations. LRTs were highest for norovirus at the 5-people scale and for adenovirus at the 100- and 1000-people scales. Example treatment trains were designed to meet the 95 % quantiles of LRTs. Treatment trains consisted of an aerated membrane bioreactor, chlorination, and, if required, UV disinfection. In most cases, rotavirus, norovirus, adenovirus and Cryptosporidium spp. determined the overall treatment train requirements. Norovirus was most often critical to dimension the chlorination (concentration × time values) and adenovirus determined the required UV dose. Smaller collection scales did not generally allow for simpler treatment trains due to the high LRTs associated with viruses, with the exception of recirculating washing machines and handwashing stations. Similarly, treating greywater sources individually resulted in lower LRTs, but the lower required LRTs nevertheless did not generally allow for simpler treatment trains. For instance, LRTs for a recirculating washing machine were around 3-log units lower compared to LRTs for indoor reuse of combined greywater (1000-people scale), but both scenarios necessitated treatment with a membrane bioreactor, chlorination and UV disinfection. However, simpler treatment trains may be feasible for small-scale and application-scale reuse if: (i) less conservative health benchmarks are used for household-based systems, considering the reduced relative importance of treated greywater in pathogen transmission in households, and (ii) higher log-removal values (LRVs) can be validated for unit processes, enabling simpler treatment trains for a larger number of appliance-scale reuse systems.
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Affiliation(s)
- Eva Reynaert
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland; ETH Zürich, Institute of Environmental Engineering, 8093 Zürich, Switzerland
| | - Émile Sylvestre
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
| | - Eberhard Morgenroth
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland; ETH Zürich, Institute of Environmental Engineering, 8093 Zürich, Switzerland
| | - Timothy R Julian
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland; Swiss Tropical and Public Health Institute, 4123 Allschwil, Switzerland; University of Basel, 4055 Basel, Switzerland.
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Reynaert E, Nagappa D, Sigrist JA, Morgenroth E. Ensuring microbial water quality for on-site water reuse: Importance of online sensors for reliable operation. WATER RESEARCH X 2024; 22:100215. [PMID: 38831972 PMCID: PMC11144787 DOI: 10.1016/j.wroa.2024.100215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Accepted: 02/21/2024] [Indexed: 06/05/2024]
Abstract
A growing number of cities and regions are promoting or mandating on-site treatment and reuse of wastewater, which has resulted in the implementation of several thousand on-site water reuse systems on a global scale. However, there is only limited information on the (microbial) water quality from implemented systems. The focus of this study was on two best-in-class on-site water reuse systems in Bengaluru, India, which typically met the local water quality requirements during monthly compliance testing. This study aimed to (i) assess the microbial quality of the reclaimed water at a high temporal resolution (daily or every 15 min), and (ii) explore whether measurements from commercially available sensors can be used to improve the operation of such systems. The monitoring campaign revealed high variations in microbial water quality, even in these best-in-class systems, rendering the water inadequate for the intended reuse applications (toilet flushing and landscape irrigation). These variations were attributed to two key factors: (1) the low frequency of chlorination, and (2) fluctuations of the chlorine demand of the water, in particular of ammonium concentrations. Such fluctuations are likely inherent to on-site systems, which rely on a low level of process control. The monitoring campaign showed that the microbial water quality was most closely related to oxidation-reduction potential (ORP) and free chlorine sensors. Due to its relatively low cost and low need for maintenance, the ORP emerges as a compelling candidate for automating the chlorination to effectively manage variations in chlorine demand and ensure safe water reuse. Overall, this study underscores the necessity of integrating treatment trains, operation, and monitoring for safe on-site water reuse.
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Affiliation(s)
- Eva Reynaert
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
- ETH Zürich, Institute of Environmental Engineering, Zürich 8093, Switzerland
| | - Deepthi Nagappa
- Ashoka Trust for Research in Ecology and the Environment (ATREE), Bengaluru 560064, India
| | - Jürg A. Sigrist
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
| | - Eberhard Morgenroth
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
- ETH Zürich, Institute of Environmental Engineering, Zürich 8093, Switzerland
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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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Pecson B, Kaufmann A, Sharvelle S, Post B, Leverenz H, Ashbolt N, Olivieri A. Risk-based treatment targets for onsite non-potable water systems using new pathogen data. JOURNAL OF WATER AND HEALTH 2022; 20:1558-1575. [PMID: 36308499 DOI: 10.2166/wh.2022.135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Using local sources (roof runoff, stormwater, graywater, and onsite wastewater) to meet non-potable water demands can minimize potable water use in buildings and increase supply reliability. In 2017, an Independent Advisory Panel developed a risk-based framework to identify pathogen log reduction targets (LRTs) for onsite non-potable water systems (ONWSs). Subsequently, California's legislature mandated the development and adoption of regulations-including risk-based LRTs-for use in multifamily residential, commercial, and mixed-use buildings. A California Expert Panel was convened in 2021 to (1) update the LRT requirements using new, quantitative pathogen data and (2) propose treatment trains capable of meeting the updated LRTs. This paper presents the updated risk-based LRTs for multiple pathogens (viruses, protozoa, and bacteria) and an expanded set of end-uses including toilet flushing, clothes washing, irrigation, dust and fire suppression, car washing, and decorative fountains. The updated 95th percentile LRTs required for each source water, pathogen, and end-use were typically within 1-log10 of the 2017 LRTs regardless of the approach used to estimate pathogen concentrations. LRT requirements decreased with influent pathogen concentrations from wastewater to graywater to stormwater to roof runoff. Cost and footprint estimates provide details on the capital, operations and maintenance, and siting requirements for ONWS implementation.
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Affiliation(s)
- Brian Pecson
- Trussell Technologies, 1939 Harrison Street, Oakland, California 94612, USA E-mail:
| | - Anya Kaufmann
- Trussell Technologies, 1939 Harrison Street, Oakland, California 94612, USA E-mail:
| | - Sybil Sharvelle
- Colorado State University, Scott Bioengineering Building 246, Fort Collins, Colorado 80523, USA
| | - Brie Post
- Trussell Technologies, 1939 Harrison Street, Oakland, California 94612, USA E-mail:
| | - Harold Leverenz
- Department of Civil and Environmental Engineering, University of California, Davis, California 95616, USA
| | - Nicholas Ashbolt
- Faculty of Science and Engineering, Southern Cross University, Military Road, East Lismore, New South Wales 2480, Australia
| | - Adam Olivieri
- EOA, Inc., 1410 Jackson Street, Oakland, California 94612, USA
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Schoen ME, Jahne MA, Garland J, Ramirez L, Lopatkin AJ, Hamilton KA. Quantitative Microbial Risk Assessment of Antimicrobial Resistant and Susceptible Staphylococcus aureus in Reclaimed Wastewaters. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:15246-15255. [PMID: 34699171 PMCID: PMC8721656 DOI: 10.1021/acs.est.1c04038] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The annual risks of colonization, skin infection, bloodstream infection (BSI), and disease burden from exposures to antibiotic-resistant and susceptible Staphylococcus aureus (S. aureus) were estimated using quantitative microbial risk assessment (QMRA). We estimated the probability of nasal colonization after immersion in wastewater (WW) or greywater (GW) treated across a range of treatment alternatives and subsequent infection. Horizontal gene transfer was incorporated into the treatment model but had little effect on the predicted risk. The cumulative annual probability of infection (resulting from self-inoculation) was most sensitive to the treatment log10 reduction value (LRV), S. aureus concentration, and the newly calculated morbidity ratios and was below the health benchmark of 10-4 infections per person per year (ppy) given a treatment LRV of roughly 3.0. The predicted annual disability-adjusted life years (DALYs), which were dominated by BSI, were below the health benchmark of 10-6 DALYs ppy for resistant and susceptible S. aureus, given LRVs of 4.5 and 3.5, respectively. Thus, the estimated infection risks and disease burdens resulting from nasal colonization are below the relevant health benchmarks for risk-based, nonpotable, or potable reuse systems but possibly above for immersion in minimally treated GW or WW. Strain-specific data to characterize dose-response and concentration in WW are needed to substantiate the QMRA.
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Affiliation(s)
- Mary E Schoen
- Soller Environmental, LLC, 3022 King Street, Berkeley, California 94703, United States
| | - Michael A Jahne
- U.S. Environmental Protection Agency, Office of Research and Development, 26 W. Martin Luther King Drive, Cincinnati, Ohio 45268, United States
| | - Jay Garland
- U.S. Environmental Protection Agency, Office of Research and Development, 26 W. Martin Luther King Drive, Cincinnati, Ohio 45268, United States
| | - Lucia Ramirez
- School of Mathematical and Statistical Sciences, Arizona State University, Tempe, Arizona 85281, United States
| | - Allison J Lopatkin
- Department of Biology, Barnard College, New York, New York 10027, United States
- Department Ecology, Evolution, and Environmental Biology, Columbia University, New York, New York 10027, United States
- Data Science Institute, Columbia University, New York, New York 10027, United States
- Department of Systems Biology, Columbia University, New York, New York 10027, United States
| | - Kerry A Hamilton
- School of Sustainable Engineering and the Built Environment, 660 S College Avenue, Tempe Arizona 85281, United States
- The Biodesign Center for Environmental Health Engineering, 1001 S McAllister Avenue, Tempe Arizona 85287, United States
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Garner E, Organiscak M, Dieter L, Shingleton C, Haddix M, Joshi S, Pruden A, Ashbolt NJ, Medema G, Hamilton KA. Towards risk assessment for antibiotic resistant pathogens in recycled water: a systematic review and summary of research needs. Environ Microbiol 2021; 23:7355-7372. [PMID: 34632683 DOI: 10.1111/1462-2920.15804] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 09/30/2021] [Accepted: 10/04/2021] [Indexed: 11/26/2022]
Abstract
Risk assessment is critical for identifying target concentrations of antibiotic resistant pathogens necessary for mitigating potential harmful exposures associated with water reuse. However, there is currently limited available data characterizing the concentrations of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) in recycled water to support robust efforts at risk assessment. The objective of this systematic review was to identify and synthesize the existing literature documenting the presence and abundance of ARB and ARGs in recycled water. In addition, this review identifies best practices and explores monitoring targets for studying ARB and ARGs in recycled water to guide future work and identifies key research needs aimed at better supporting quantitative microbial risk assessment focused on recycled water and antibiotic resistance. Future efforts to collect data about ARB and ARG prevalence in recycled water should report concentration data per unit volume. Sample metadata should also be provided, including a description of treatment approach, a description of planned water uses (e.g., potable, irrigation), methods for conveyance to the point of use, and available physicochemical water quality data. Additional research is needed aimed at identifying recommended ARB and ARG monitoring targets and for developing approaches to incorporate metagenomic data into risk assessment.
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Affiliation(s)
- Emily Garner
- Wadsworth Department of Civil and Environmental Engineering, West Virginia University, Morgantown, WV, 26506, USA
| | - Marisa Organiscak
- Wadsworth Department of Civil and Environmental Engineering, West Virginia University, Morgantown, WV, 26506, USA
| | - Lucien Dieter
- School of Sustainable Engineering and the Built Environment, Arizona State University, 660 S College Ave, Tempe, AZ, 85281, USA.,The Biodesign Institute Center for Environmental Health Engineering, Arizona State University, 1001 S McAllister Ave, Tempe, AZ, 85281, USA
| | - Carley Shingleton
- Wadsworth Department of Civil and Environmental Engineering, West Virginia University, Morgantown, WV, 26506, USA
| | - Madison Haddix
- Wadsworth Department of Civil and Environmental Engineering, West Virginia University, Morgantown, WV, 26506, USA
| | - Sayalee Joshi
- School of Sustainable Engineering and the Built Environment, Arizona State University, 660 S College Ave, Tempe, AZ, 85281, USA.,The Biodesign Institute Center for Environmental Health Engineering, Arizona State University, 1001 S McAllister Ave, Tempe, AZ, 85281, USA
| | - Amy Pruden
- Via Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, VA, 24061, USA
| | - Nicholas J Ashbolt
- Faculty of Science and Engineering, Southern Cross University, Lismore, Australia
| | - Gertjan Medema
- KWR Water Research Institute, 7 3433PE, Nieuwegein, The Netherlands.,Sanitary Engineering, Delft University of Technology, Stevinweg 1 2628 CN Delft, Nieuwegein, The Netherlands
| | - Kerry A Hamilton
- School of Sustainable Engineering and the Built Environment, Arizona State University, 660 S College Ave, Tempe, AZ, 85281, USA.,The Biodesign Institute Center for Environmental Health Engineering, Arizona State University, 1001 S McAllister Ave, Tempe, AZ, 85281, USA
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