NSF Org: |
CBET Div Of Chem, Bioeng, Env, & Transp Sys |
Recipient: |
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Initial Amendment Date: | March 17, 2020 |
Latest Amendment Date: | May 19, 2021 |
Award Number: | 2027049 |
Award Instrument: | Standard Grant |
Program Manager: |
Bruce Hamilton
bhamilto@nsf.gov (703)292-0000 CBET Div Of Chem, Bioeng, Env, & Transp Sys ENG Directorate For Engineering |
Start Date: | April 1, 2020 |
End Date: | December 31, 2022 (Estimated) |
Total Intended Award Amount: | $200,000.00 |
Total Awarded Amount to Date: | $216,000.00 |
Funds Obligated to Date: |
FY 2021 = $16,000.00 |
History of Investigator: |
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Recipient Sponsored Research Office: |
2550 NORTHWESTERN AVE # 1100 WEST LAFAYETTE IN US 47906-1332 (765)494-1055 |
Sponsor Congressional District: |
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Primary Place of Performance: |
155 Grant Street West Lafayette IN US 47907-2014 |
Primary Place of Performance Congressional District: |
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Unique Entity Identifier (UEI): |
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Parent UEI: |
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NSF Program(s): |
EnvE-Environmental Engineering, Special Initiatives, EnvS-Environmtl Sustainability |
Primary Program Source: |
01002122DB NSF RESEARCH & RELATED ACTIVIT |
Program Reference Code(s): |
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Program Element Code(s): |
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Award Agency Code: | 4900 |
Fund Agency Code: | 4900 |
Assistance Listing Number(s): | 47.041 |
ABSTRACT
The explosive onset of school, business, and event venue shutdowns across the nation to encourage social distancing in response to COVID-19 will be disruptive on multiple levels. While 2-4 week shutdowns are increasingly being declared, some organizations have warned of longer closures. The proposing team's own school and office building water testing evidence indicates such extended shutdowns will have drastic consequences on building drinking water safety: chemical and microbiological water quality potentially presenting serious public health risks. As inhabitants return, they will encounter extremely stagnated water with excessive lead, copper, and bacterial concentrations, that may include pathogens like Legionella pneumophila. There are no national or industry guidelines for building reopening after extended shutdowns. A fundamental understanding of water quality deterioration mechanisms precipitated by large-scale shutdowns and plumbing decontamination is critically lacking. The Association of State and Territorial Health Officials (ASTHO) serves over 100,000 public health professionals and has made clear that building recommissioning practices are lacking. The COVID-19 building closures present a rare opportunity to study chemical-microbiological-physical- material interactions in multiple otherwise operational buildings. At both full- and bench-scales, the team will (1) characterize disinfectant, heavy metal, and bacterial changes during extended building closures, and (2) develop evidence-based plumbing remediation methods to address water quality deterioration.
Using a college campus affected by COVID-19, water quality will be characterized in closed or under- utilized buildings over the course of 5 months (Objective 1). All in-person class meetings have been cancelled for spring semester at Purdue, while research activities can continue, allowing real-scale study of buildings impacted by closure. Before fall semester, decontamination procedures will be tested (Objective 2). Bench-scale experiments will be conducted in parallel to simulate water use conditions and probe the fundamental factors that influenced deterioration and plumbing decontamination effectiveness. The team will elucidate the fundamental factors that control extreme chemical and microbiological transformations in plumbing that are occurring nationwide during the COVID-19 outbreak, as well as during many other disasters.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH
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PROJECT OUTCOMES REPORT
Disclaimer
This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.
Purpose
This project was initiated in response to the Coronavirus disease (COVID)-19 pandemic. The explosive onset of school, business, and event venue closings across the nation prompted global questions about water safety. Would the water be safe to use when the buildings were reopened? What about the safety of the people inside these low water use buildings? The lack of national and industry guidelines for building reopening -as it related to water safety- inhibited clear building operation and management decisions that were protective of public health.
Approach
Several studies were conducted to determine how extended water stagnation impacted cold and hot water safety. This study explored water quality inside school, office, and institutional buildings that were shutdown. Water was screened for chemicals like heavy metals (copper, lead, manganese, etc.). Water was also tested for disease-causing microorganisms like Legionella. For a more controlled environment, the impact of stagnation time on water quality was tested in four identical plumbing laboratory setups. Water softeners were also purchased from a major plumbing supplier and were tested.
Discoveries
GENERAL: The lack of official universal U.S. and industry plumbing flushing procedures and the scientific understanding about how to create those procedures prompted public health concerns nationwide. In the course of this project, the team found that building owners generally wanted to reduce the chance that unsafe water reached people in their buildings. Due to the lack of guidance available, some building owners haphazardly flushed fixtures, with no measurable sustaining improvement on water quality. For buildings that had hundreds of faucets, owners often did not have the labor required to conduct a complete building flush or repeated flushing.
IN BUILDINGS: When water was tested in buildings that had been closed for months, heavy metals like copper, lead, manganese, and nickel sometimes exceeded safe limits, but widespread contamination (at every fixture in every building) was not found. To address these issues, one recommendation to building owners was to flush fixtures before reopening. Though, flushing by contractors hired by one building owner caused scale destabilization and increased heavy metal levels temporarily until flushing was completed. To reduce heavy metal contamination, there was no "one size fits all" flushing time that worked for all fixtures in a single building (or across buildings). For example, in one building flushing 5 minutes resulted in detectable chlorine residual to the faucet in 3 buildings, while no residual chlorine was detected even after 125 minutes of flushing in the largest and oldest building of that study. Building owners should design flushing procedures based on the actual design of their plumbing, and this type of protocol can be required during building commissioning.
Screening water for the pathogen Legionella pneumophila was a primary focus in this project. This organism was detected in some building water systems. Legionella was detected not just in hot water, but was also found in cold water (i.e., water fountains, etc.). While some organizations had recommended shock disinfection to reduce the levels of this organism in plumbing, this project found that sometimes flushing alone was effective. For one building, a private company conducted shock disinfection and Legionella was detected immediately after disinfection. This detection was likely due to the organisms being released from biofilm during the aggressive flushing process. Legionella was not detected weeks later from that plumbing. No national or industry protocols were found that determined what metrics were most important determining plumbing disinfection effectiveness.
WATER SOFTENERS: New drinking water softeners were found to leach excessive levels of carbon and sulfur into drinking water, and potentially microplastics. These discoveries underscore the need for the devices to be thoroughly flushed before use. Softeners were also found to be susceptible to hydrocarbon chemical. Once contaminated, the softener resin still leached hydrocarbons more than 2 weeks after the flush-out.
MOCK PLUMBING SYSTEMS: For 6 months, four full-scale plumbing setups underwent weekly flushing, daily flushing, and intermittent flushing. Testing revealed that chlorine residual, meant to minimize microorganism growth in plumbing, was rarely present in stagnant samples. Regular weekly flushing was not sufficient to minimize microorganisms growing in the plumbing. Legionella spp. was found and most often positive when weekly flushing was used. The working conclusion is that only the daily plumbing flushing action controlled microorganism levels.
Knowledge Sharing
Results were shared publicly through websites, social media, interviews with TV, radio, and other media. The project team responded directly to building owners, health officials, and inhabitants (i.e., parents of school children) who requested information about water safety in buildings. Studies were under review by scientific journals at the time this report summary was created. Once approved, links to the studies will be available at https://www.PlumbingSafety.org. Results were presented at more than 50 events hosted by building construction, public health, plumbing technology, engineering, and green building organizations, and university seminars and symposiums.
Last Modified: 05/03/2023
Modified by: Andrew J Whelton
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