Grantee Research Project Results
2017 Progress Report: Early Career Award: Framework for Quantifying Microbial Risk and Sustainability of Potable Reuse Systems in the United States
EPA Grant Number: R835823Title: Early Career Award: Framework for Quantifying Microbial Risk and Sustainability of Potable Reuse Systems in the United States
Investigators: Gerrity, Daniel
Institution: University of Nevada - Las Vegas
EPA Project Officer: Packard, Benjamin H
Project Period: August 1, 2015 through July 31, 2018
Project Period Covered by this Report: August 1, 2016 through July 31,2017
Project Amount: $329,650
RFA: Human and Ecological Health Impacts Associated with Water Reuse and Conservation Practices (2014) RFA Text | Recipients Lists
Research Category: Water , Human Health
Objective:
This research addresses three critical issues related to the spectrum of potable reuse applications in the United States: (1) quantifying the microbial and
chemical risks associated with various treatment trains in de facto, "planned" indirect potable reuse (IPR), and direct potable reuse (DPR) paradigms; (2) developing a framework for comparing the sustainability of IPR versus DPR; and (3) evaluating alternative treatment trains based on the formation and mitigation of disinfection byproducts (DBPs) and other contaminants of emerging concern (CECs). The research is intended to demonstrate that "planned" potable reuse offers a safe and sustainable alternative to conventional drinking water practices.
Progress Summary:
With respect to task 1, the project team completed the first quantitative microbial risk assessment (QMRA) model that compares risk of cryptosporidiosis in de facto reuse, planned IPR, and DPR systems. The model confirmed that IPR and DPR generally provide robust barriers against Cryptosporidium and that risks associated with potable reuse are generally comparable to or lower than those of conventional drinking water systems. The resiliency provided by the environmental buffer proved to be critically important, particularly under failure conditions. Risk decreased with increasing recycled water contribution in the de facto reuse and planned IPR systems when considering a storage time of 270 days. Shorter storage times had minimal impact on planned IPR, but the annual risk exceeded the 10-4 benchmark for some de facto reuse scenarios when the storage time was shortened to less than 105 days. With respect to task 2, the project team developed a draft of the system dynamics model that will be used to compare the sustainability of IPR vs. DPR in Las Vegas. The model is currently being calibrated and will be completed by the end of 2017. With respect to task 3, the project team completed research related to trihalomethane (THM) and haloacetic acid (HAA) formation potential in ozonebiofiltration effluents and developed models to predict formation potential as a function of effluent total organic carbon (TOC) concentrations. The project team also completed preliminary assessments of NDMA mitigation, including evaluations of media type, media history, and redox conditions. Finally, as part of education and outreach, the project team produced a short film highlighting potable reuse in Las Vegas.
Future Activities:
With respect to task 1, the project team will extend the current QMRA model to bacteria and viruses and also will include a treatment train employing reverse osmosis. This model will incorporate hydrodynamic variability in the environmental buffer and variable unit process performance based on results from a recent full-scale monitoring study. A third QMRA model will be developed to account for disease transmission and to include a feedback loop linking changes in public health risk to raw sewage concentrations of target pathogens. With respect to task 2, the project team will complete the system dynamics model comparing the sustainability of IPR vs. DPR in Las Vegas. With respect to task 3, the project team will complete the evaluation of operational conditions in ozone-biofiltration systems and their effects on NDMA and TOrC mitigation. In the fall of 2017, the project team expects to submit two peer-reviewed manuscripts detailing the (1) THM/HAA experiments and (2) microbial community characterization of the biofiltration columns. Peer-reviewed publications for the other components of the project will be prepared as the models and experimental data are finalized.
Journal Articles on this Report : 1 Displayed | Download in RIS Format
Other project views: | All 23 publications | 3 publications in selected types | All 3 journal articles |
---|
Type | Citation | ||
---|---|---|---|
|
Amoueyan E, Ahmad S, Eisenberg JNS, Pecson B, Gerrity D. Quantifying pathogen risks associated with potable reuse: a risk assessment case study for Cryptosporidium. Water Research 2017;119:252–266. |
R835823 (2016) R835823 (2017) R835823 (Final) |
Exit Exit Exit |
Supplemental Keywords:
Drinking water, decision making, engineeringRelevant Websites:
The following websites contain information related to this EPA-funded research. The first is an episode of UNLV Research Files highlighting the project (22:45), and the second is a short film produced by the project team that describes potable reuse in Las Vegas.
Link 1: http://unlvtv.unlv.edu/research-files-404/ Exit
Link 2: https://vimeo.com/221765588 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.