Grantee Research Project Results
2020 Progress Report: Water Conservation and Water Quality: Understanding the Impacts of New Technologies and New Operational Strategies
EPA Grant Number: R836880Title: Water Conservation and Water Quality: Understanding the Impacts of New Technologies and New Operational Strategies
Investigators: Gurian, Patrick , Olson, Mira S. , Haas, Charles N. , Summers, R. Scott , Clancy, Jennifer , Masters, Sheldon , Treado, Steven
Institution: Drexel University , Pennsylvania State University , University of Colorado at Boulder
EPA Project Officer: Packard, Benjamin H
Project Period: October 1, 2016 through September 30, 2019 (Extended to September 30, 2021)
Project Period Covered by this Report: October 1, 2019 through September 30,2020
Project Amount: $1,989,000
RFA: National Priorities: Impacts of Water Conservation on Water Quality in Premise Plumbing and Water Distribution Systems (2016) RFA Text | Recipients Lists
Research Category: Ecological Indicators/Assessment/Restoration , Climate Change , Water
Objective:
The project combines literature information with novel experimental results to develop and validate predictive models of the risk of failing to meet water quality goals for premise plumbing. Guidance information will be encoded in a web-based decision support tool usable by facilities managers and utility personnel to identify high risk conditions for premise plumbing water quality and potential remedial actions.
Progress Summary:
Key highlights of the results and outcomes to date are summarized in the section A above. A brief summary overview is provided below.
The research efforts of the project team are divided into the following four broad task categories:
o Task 1: QMRA informed water quality standards for built environments: Setting critical acceptable concentrations for OPPPs in built environments
o Task 2: Experts and practitioners consultations, knowledge synthesis, and meta-analyses
o Task 3: Experimental investigation of water quality issues in premise plumbing: Pipe rack and hot water tank experiments
o Task 4: Development of a decision support tool
A summary of the key accomplishments for each research task are given below.
Task 1: QMRA based water quality standards for built environments: Setting critical acceptable concentrations for OPPPs in built environments
Our efforts under this task are focused on setting threshold concentrations for various Opportunistic Premise Plumbing Pathogens (OPPPs) in different building environmental exposure scenarios. Quantitative Microbial Risk Assessment (QMRA) approach was used to identify target concentrations that meet risk-based goals for human health protection. Much of the work on this task was completed by the third year of the project. Models were developed for calculating risk-based critical concentrations of Legionella pneumophila (10.1021/acs.est.8b03000) and Pseudomonas Aeruginosa and Naegleria Fowleri (10.3390/w11091850) critical concentrations under different building environment exposure scenarios. The details of these studies have been described in the annual reports of previous years. During the current reporting year we have further leveraged efforts by Dr. Hamilton’s lab at Arizona State University, and collaborated with her on developing similar QMRA models to determine critical concentrations of Mycobacterium avium complex (MAC) for various indoor residential water uses. USEPA’s annual risk benchmark of 1 in 10,000 for drinking water-related infections was considered for a set of exemplary exposure scenarios. These scenarios include different combinations of three indoor water fixture types (showers, toilets, and faucets), two fixture designs (conventional vs. water efficient), two exposure routes (ingestion of drinking water and inhalation of aerosols), three population types (general, children, and immunocompromised), and three health endpoints (pulmonary infection, cervical lymphadenitis, and disseminated infections). A manuscript based on this study is under peer review.
Task 2: Experts and practitioners consultation, knowledge synthesis, and meta-analyses
One set of subtasks under Task 2 are focused on devising appropriate guidelines and management strategies and identifying knowledge gaps in maintaining water quality in building plumbing systems though subject matter experts (SMEs) and facility managers (FMs) consultations, review of existing guidance information (GDs), and the Delphi approach of assessing consensus among experts’ knowledge. A peer reviewed manuscript based on SME consultations and available guidance information synthesis was published in the journal Water earlier this year (10.3390/w12020347). Further, to understand realistic ground situation among practitioners on water quality management practices prevalent in buildings in the United States, building facility manager interviews were conducted. Semi-structured phone surveys and structured online surveys were conducted with 41 building facility managers about building plumbing system management practices in their buildings. The aim of this study was to compare the existing management practices with the available guidance and identify the potential problematic spots in their buildings. The results show that most of the surveyed buildings were not in compliance with the temperature recommendations for Legionella control in buildings. Instead scald risk concern seem to dominate and a large majority of buildings complied with scalding guidance. Plumbing elements associated with the modern building plumbing systems, electronic faucets, thermostatic mixing valve, flexible shower hoses, etc. were found to be among top problematic spots, particularly in buildings with vulnerable populations. An advanced draft of a manuscript based on this study is ready for peer review submission. Lastly, a Delphi study- consisting of multiple rounds of experts surveys- on building water quality management is also currently underway. A questionnaire on building water quality issues was developed after iterative consultation with an internal group of experts. A diverse group of 104 external experts were contacted for the 1st round of participation and a total 34 responses were elicited. The first round of data analysis is currently underway. Up to two more rounds of interviews will be conducted to reach consensus on the maximum number of issues. We expect to publish a peer reviewed manuscript based on this study.
Another set of subtasks under Task 2 are focused on compiling evidence for water quality management in buildings through systematic literature review and meta-analyses. One such effort focused on investigating hot water temperature and Legionella colonization in hotel plumbing systems to optimize temperature control of Legionella. Qualitative synthesis and quantitative analysis were performed on 13 studies identified from the literature by systematic search. The analyses identified 55 0C as a cutoff point for plumbing hot water temperature and found a strong negative association between temperature and Legionella colonization. A logistic regression analysis of hot water temperature and Legionella detection found a temperature of 59 0C associated with an 8% probability of detectable Legionella . A peer reviewed manuscript based on this study was published in the journal Water Research earlier this year (10.1016/j.watres.2020.115943). A similar systematic literature review and meta-analysis study is currently underway to identify the effectiveness of free chlorine and chloramine disinfectants for controlling OPPPs, Mycobacterium avium complex and Legionella. A systematic literature search identified over 5000 studies that are currently being screened for relevancy as per PRISMA framework. We expect to publish a peer reviewed manuscript based on this study.
Task 3: Experimental investigation of water quality issues in premise plumbing: Pipe rack and hot water tanks experiments
Under this task, experimental investigations were conducted on the different issues related to water quality in building plumbing systems, viz, residual decay, microbial growth, and DBPs formation. In first set of experiments experimental set ups simulating cold water plumbing systems in buildings (pipe racks) and hot water systems (water heater tanks) were set-up in Philadelphia, PA (chloramine disinfectant) and Boulder, CO (free chlorine disinfectant). Multiple studies were conducted in these set ups. First, a full factorial study of pipe characteristics (material and diameter) and stagnation time on residual decay in free chlorine and chloramine pipe rack systems. Copper pipes consumed more residual than other plastic pipes and so did the smaller pipes in chloramine systems. Nitrification was observed for as low as a 12-hour stagnation period. A peer reviewed manuscript based on this study was published in the journal AWWA Water Science earlier this year (10.1002/aws2.1204). Analyses on microbial growth and DBP formation in pipe rack experiments are also being conducted. For water heater tank experiments, one study focused on investigating water quality decay in hot water plumbing systems in the buildings in terms of residual decay and microbial growth. The results show that higher residence time in the hot water tank, i.e. low use frequency, causes more decay of both chlorine and chloramine disinfectants and usually little or no residual persists when free chlorine is used. For microbial growth, chloramine was but not effective for NTM control. A manuscript draft from this study is in preparation. The data for DBP formation is also being analyzed.
Task 4: Development of a decision support tool
Our efforts under this task consist of summarizing the information from Task 2 above (and other tasks as well wherever possible) in context to help facility mangers find solutions to the water quality issues in their buildings. To that effect, we have developed a guidance summaries database of various potential water quality issues in the buildings based on the knowledge base we have built through SMEs and facility managers consultations and guidance review studies. We have also developed decision trees on various plumbing situations that the facility managers may encounter in their plumbing systems to help assess water quality in their buildings and provide remediation actions based on the comprehensive guidance summaries and knowledge synthesis database we have prepared. These decision trees and knowledge database are currently being coded in an online decision support tool (DST), herein named as the “Plumbing Information and Performance Evaluation (PIPE) decision support tool.” The PIPE decision support tool is currently under construction (http://www.pages.drexel.edu/~lm3388/DSTProject/index.html), and once ready it will provide a free resource for building facility managers to assess water quality in their buildings by simply answering questions related to their building inhabitants and plumbing operational parameters and design features. PIPE will help the users to identify potentially problematic features in their building plumbing and may suggest potential management needs/actions. Once in operation, we intend to beta-test among the targeted users (i.e., building owners, engineers, facility managers) to identify opportunities to improve the tool. A conference abstract has been accepted for full paper in conference proceeding at ASCE-EWRI conference in May 2021, and we expect a full peer reviewed journal publication at completion of this study.
Future Activities:
Some of the key activities for Year 5 include complete data analyses and prepare manuscripts for publications. Completed decision support toll will be deployed online, and data will be collected during beta-testing to make further improvements.
Journal Articles on this Report : 6 Displayed | Download in RIS Format
Other project views: | All 42 publications | 7 publications in selected types | All 7 journal articles |
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Hamilton KA, Prussin AJ, Ahmed W, Haas CN. Outbreaks of legionnaires’ disease and pontiac fever 2006–2017. Current environmental health reports 2018;5(2):263-71. |
R836880 (2020) R836880 (Final) |
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Rasheduzzaman M, Singh R, Haas CN, Tolofari D, Yassaghi H, Hamilton KA, Yang Z, Gurian PL. Reverse QMRA as a decision support tool:setting acceptable concentration limits for Pseudomonas aeruginosa and Naegleria fowleri. Water 2019;11(9):1850. |
R836880 (2019) R836880 (2020) R836880 (Final) |
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Hamilton KA, Hamilton MT, Johnson W, Jjemba P, Bukhari Z, LeChevallier M, Haas CN, Gurian PL. Risk-based critical doncentrations of Legionella pneumophila for indoor residential water uses. Environmental Science & Technology 2019;53(8):4528-4541. |
R836880 (2019) R836880 (2020) R836880 (Final) |
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Tolofari DL, Masters SV, Bartrand T, Hamilton KA, Haas CN, Olson M, Summers RS, Rasheduzzaman M, Young A, Singh R, Gurian PL. Full factorial study of pipe characteristics, stagnation times, and water quality. AWWA Water Science 2020;2(5):e1204. |
R836880 (2020) R836880 (Final) |
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Singh R, Hamilton KA, Rasheduzzaman M, Yang Z, Kar S, Fasnacht A, Masters SV, Gurian PL. Managing Water Quality in Premise Plumbing:Subject Matter Experts’ Perspectives and a Systematic Review of Guidance Documents. Water 2020;12(2):347. |
R836880 (2020) R836880 (Final) |
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Rasheduzzaman M, Singh R, Haas CN, Gurian PL. Required water temperature in hotel plumbing to control Legionella growth. Water Research 2020:115943. |
R836880 (2020) R836880 (Final) |
Exit |
Supplemental Keywords:
Opportunistic premise plumbing pathogens (OPPPs); Reverse quantitative microbial risk assessment (QMRA); Legionella pneumophila; Building water quality; Green buildings; Efficient water fixtures, Premise plumbing, Disinfection residuals, Disinfection byproductsRelevant Websites:
Building Water Quality Exit , Special Issue "Water Quality in Buildings" Exit ,
Progress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.