Margaret E. Carolan, Richard J. Langel, Dustin May, Anthony DeSalvo, Humberto E. Gonzalez-Ribot, Alyssa J. Mattson, Michael D. Schueller, Darrin A. Thompson, David M. Cwiertny, Tori Z. Forbes
Radium is a naturally-occurring radioactive element found in Upper Midwest aquifers, yet exposure risks for unregulated water sources in this region are unknown. A survey of 226/228Ra and other inorganic constituents in 94 private wells was conducted in 2019 across 10 Iowa counties. Within private wells, 53% measured below minimum detectable activity whereas 6.3% have 226/228Ra levels above the United States Environmental Protection Agency Maximum Contaminant Level. 226/228Ra occurrence was not associated with well-depth or chemical surrogates, but were generally consistent with the lithology and historical water quality trends for aquifers. In 2020, 11 of the 226/228Ra-impacted wells were re-sampled to assess the efficacy of in-home water treatment. Water softeners reduced 226/228Ra to non-detectable activities, but other inorganic constituents persisted and their removal required more advanced treatment. This study suggests that 226/228Ra occurrence in private wells can reasonably be anticipated from public water supply data if reliable information is available to identify the source aquifer.
{"title":"Survey of 226Ra/228Ra and inorganic constituents in Iowa private drinking water wells","authors":"Margaret E. Carolan, Richard J. Langel, Dustin May, Anthony DeSalvo, Humberto E. Gonzalez-Ribot, Alyssa J. Mattson, Michael D. Schueller, Darrin A. Thompson, David M. Cwiertny, Tori Z. Forbes","doi":"10.1002/aws2.1311","DOIUrl":"10.1002/aws2.1311","url":null,"abstract":"<p>Radium is a naturally-occurring radioactive element found in Upper Midwest aquifers, yet exposure risks for unregulated water sources in this region are unknown. A survey of <sup>226/228</sup>Ra and other inorganic constituents in 94 private wells was conducted in 2019 across 10 Iowa counties. Within private wells, 53% measured below minimum detectable activity whereas 6.3% have <sup>226/228</sup>Ra levels above the United States Environmental Protection Agency Maximum Contaminant Level. <sup>226/228</sup>Ra occurrence was not associated with well-depth or chemical surrogates, but were generally consistent with the lithology and historical water quality trends for aquifers. In 2020, 11 of the <sup>226/228</sup>Ra-impacted wells were re-sampled to assess the efficacy of in-home water treatment. Water softeners reduced <sup>226/228</sup>Ra to non-detectable activities, but other inorganic constituents persisted and their removal required more advanced treatment. This study suggests that <sup>226/228</sup>Ra occurrence in private wells can reasonably be anticipated from public water supply data if reliable information is available to identify the source aquifer.</p>","PeriodicalId":101301,"journal":{"name":"AWWA water science","volume":"4 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://awwa.onlinelibrary.wiley.com/doi/epdf/10.1002/aws2.1311","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89138524","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Recent data showing fast degradation of the emerging disinfection by-product 2,6-dichloro-1,4-benzoquinone (DCBQ) in the presence of free chlorine seem incompatible with the high concentrations reported in drinking water distribution systems. The current study was conducted to reconcile this apparent incompatibility. Laboratory tests showed that the published protocol for DCBQ preservation, addition of formic acid without conventional reducing agents, was problematic. Formic acid does not rapidly reduce free chlorine, allowing chlorine residuals to persist during sample workup and analysis. Acidic conditions from formic acid addition along with a persistent free chlorine residual catalyzed additional DCBQ formation when organic precursors were present. This led to large positive analytical bias during formation potential testing using raw water and model precursors. DCBQ levels previously reported using the formic acid preservation method are likely to show a strong positive bias. For future testing, we recommend the use of glycine or arsenite followed by formic acid.
{"title":"Discrepancies and artifacts during preservation and analysis of the disinfection by-product 2,6-dichloro-1,4-benzoquinone","authors":"Aarthi Mohan, David A. Reckhow","doi":"10.1002/aws2.1310","DOIUrl":"10.1002/aws2.1310","url":null,"abstract":"<p>Recent data showing fast degradation of the emerging disinfection by-product 2,6-dichloro-1,4-benzoquinone (DCBQ) in the presence of free chlorine seem incompatible with the high concentrations reported in drinking water distribution systems. The current study was conducted to reconcile this apparent incompatibility. Laboratory tests showed that the published protocol for DCBQ preservation, addition of formic acid without conventional reducing agents, was problematic. Formic acid does not rapidly reduce free chlorine, allowing chlorine residuals to persist during sample workup and analysis. Acidic conditions from formic acid addition along with a persistent free chlorine residual catalyzed additional DCBQ formation when organic precursors were present. This led to large positive analytical bias during formation potential testing using raw water and model precursors. DCBQ levels previously reported using the formic acid preservation method are likely to show a strong positive bias. For future testing, we recommend the use of glycine or arsenite followed by formic acid.</p>","PeriodicalId":101301,"journal":{"name":"AWWA water science","volume":"4 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://awwa.onlinelibrary.wiley.com/doi/epdf/10.1002/aws2.1310","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85231873","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ricardo Medina, Manmeet W. Pannu, Scott A. Grieco, Michael Hwang, Christine Pham, Megan H. Plumlee
Eight granular activated carbons (GAC), four anion exchange (IX) resins, and two alternative adsorbents (AAs) were tested for the removal of per- and polyfluoroalkyl substances (PFAS) from a groundwater source used for drinking water. The study was conducted using pilot(meter)-scale columns operated in continuous-flow mode for 16–26 months. Comparison between GAC adsorbents showed that bituminous GACs exhibited higher adsorption than non-/sub-bituminous GACs. Testing of a reactivated and new GAC showed no significant differences with respect to PFAS adsorption. Of the four IX resins tested, one resin showed superior adsorption when compared with all three IX resins. A surface-modified bentonite adsorbent showed superior removal efficiencies over all adsorbent types tested here. These results provide benchmark performance and adsorption capacities at pilot-scale for various adsorbents and highlight the promise of AAs to remove PFAS from water sources with low (ng/L) concentrations.
{"title":"Pilot-scale comparison of granular activated carbons, ion exchange, and alternative adsorbents for per- and polyfluoroalkyl substances removal","authors":"Ricardo Medina, Manmeet W. Pannu, Scott A. Grieco, Michael Hwang, Christine Pham, Megan H. Plumlee","doi":"10.1002/aws2.1308","DOIUrl":"10.1002/aws2.1308","url":null,"abstract":"<p>Eight granular activated carbons (GAC), four anion exchange (IX) resins, and two alternative adsorbents (AAs) were tested for the removal of per- and polyfluoroalkyl substances (PFAS) from a groundwater source used for drinking water. The study was conducted using pilot(meter)-scale columns operated in continuous-flow mode for 16–26 months. Comparison between GAC adsorbents showed that bituminous GACs exhibited higher adsorption than non-/sub-bituminous GACs. Testing of a reactivated and new GAC showed no significant differences with respect to PFAS adsorption. Of the four IX resins tested, one resin showed superior adsorption when compared with all three IX resins. A surface-modified bentonite adsorbent showed superior removal efficiencies over all adsorbent types tested here. These results provide benchmark performance and adsorption capacities at pilot-scale for various adsorbents and highlight the promise of AAs to remove PFAS from water sources with low (ng/L) concentrations.</p>","PeriodicalId":101301,"journal":{"name":"AWWA water science","volume":"4 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://awwa.onlinelibrary.wiley.com/doi/epdf/10.1002/aws2.1308","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91472064","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Successfully implementing water safety plans (WSPs) in small, municipal drinking water systems is understudied in affluent jurisdictions where WSPs are not required by regulations. We piloted a computer-based risk assessment survey in eight municipal water systems in Nova Scotia, Canada to evaluate the benefits and challenges of implementing risk assessment strategies in non-WSP jurisdictions. Semi-structured interviews were conducted with water operators and managers to gather feedback on the risk assessment survey and process. Results indicated difficulties quantifying risk despite streamlining the risk identification process, resulting in key informants viewing the risk assessment as strictly diagnostic and unlikely to be integrated into operational practice if not required. We identified a need to shift water system culture from a regulatory-based to a knowledge-based mindset for successful risk assessment implementation. Clear lines of communication, increased understanding of risk, and commitment to improvement are critical to shifting water system culture toward a risk-based water quality management approach.
{"title":"Operator-informed risk assessment tool: Opportunities and barriers to support risk management practices","authors":"Kaycie Lane, Megan Fuller, Graham Gagnon","doi":"10.1002/aws2.1307","DOIUrl":"10.1002/aws2.1307","url":null,"abstract":"<p>Successfully implementing water safety plans (WSPs) in small, municipal drinking water systems is understudied in affluent jurisdictions where WSPs are not required by regulations. We piloted a computer-based risk assessment survey in eight municipal water systems in Nova Scotia, Canada to evaluate the benefits and challenges of implementing risk assessment strategies in non-WSP jurisdictions. Semi-structured interviews were conducted with water operators and managers to gather feedback on the risk assessment survey and process. Results indicated difficulties quantifying risk despite streamlining the risk identification process, resulting in key informants viewing the risk assessment as strictly diagnostic and unlikely to be integrated into operational practice if not required. We identified a need to shift water system culture from a regulatory-based to a knowledge-based mindset for successful risk assessment implementation. Clear lines of communication, increased understanding of risk, and commitment to improvement are critical to shifting water system culture toward a risk-based water quality management approach.</p>","PeriodicalId":101301,"journal":{"name":"AWWA water science","volume":"4 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://awwa.onlinelibrary.wiley.com/doi/epdf/10.1002/aws2.1307","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73835610","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Amin Ganjidoost, Carl T. Haas, Mark A. Knight, Andre J. A. Unger
This paper presents a decision support system for the integrated management of water distribution and wastewater collection networks. The proposed methodology utilizes system dynamics to integrate water mains and sewers with finance and sociopolitical sectors. It enables user rate-setting and planning of integrated water and wastewater infrastructure operational and capital works over their life-cycle (50+ years). The integrated asset management model is implemented using data from a large-sized utility in Southern Ontario, Canada. The result indicates that the integrated framework enables the utility to accelerate funding for capital and operational works due to the integration of the water and wastewater financial resources and improve the integrated levels of service. In practice, the proposed integrated framework empowers and encourages water utilities to manage and plan their assets in an integrated approach to enhance their water and wastewater assets' infrastructure, financial, and sociopolitical performance relative to managing them in isolation.
{"title":"Integrated asset management of urban water and wastewater systems","authors":"Amin Ganjidoost, Carl T. Haas, Mark A. Knight, Andre J. A. Unger","doi":"10.1002/aws2.1309","DOIUrl":"10.1002/aws2.1309","url":null,"abstract":"<p>This paper presents a decision support system for the integrated management of water distribution and wastewater collection networks. The proposed methodology utilizes system dynamics to integrate water mains and sewers with finance and sociopolitical sectors. It enables user rate-setting and planning of integrated water and wastewater infrastructure operational and capital works over their life-cycle (50+ years). The integrated asset management model is implemented using data from a large-sized utility in Southern Ontario, Canada. The result indicates that the integrated framework enables the utility to accelerate funding for capital and operational works due to the integration of the water and wastewater financial resources and improve the integrated levels of service. In practice, the proposed integrated framework empowers and encourages water utilities to manage and plan their assets in an integrated approach to enhance their water and wastewater assets' infrastructure, financial, and sociopolitical performance relative to managing them in isolation.</p>","PeriodicalId":101301,"journal":{"name":"AWWA water science","volume":"4 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://awwa.onlinelibrary.wiley.com/doi/epdf/10.1002/aws2.1309","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91482874","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}