Collaborative Research: Relative Abundance and Diversity of Antibiotic Resistance Genes and Pathogens in Reclaimed Versus Potable Water Distribution Systems
Water sustainability, antibiotic resistance, and opportunistic pathogens represent three critical global health challenges. Expanding the use of reclaimed water is critical to advancing water sustainability. However, important knowledge gaps remain with respect to microbial risk and public health. Research results will directly benefit the water utilities and water stressed regions participating in this project by vetting existing practices and revealing new and effective management strategies that proactively address public health concerns. Results will be disseminated via peer reviewed literature, presentations at conferences attended by water professionals, and through the newsletter and other avenues sponsored by the Water Resources Research Center at U. Arizona. The project will also support Native American and other underrepresented undergraduate researchers at U. Arizona and two graduate students at Virginia Tech, who will be trained across disciplines through the Interfaces of Global Change Interdisciplinary Graduate Education Program. Additional undergraduate researchers will participate through the NSF Interdisciplinary Water Science and Engineering REU site and other NSF REU sites at Virginia Tech. The project will be an excellent training platform at the nexus of public health and sustainability, with training opportunities in the emerging field of metagenomics.
The proposed research is the first comprehensive assessment of reclaimed water distribution systems microbiome, providing insight into the occurrence and regrowth of microbial constituents of emerging concern in reclaimed water. The interplay between physico-chemistry and microbial ecology in reclaimed water distribution systems will be revealed using an integrated lab and field sampling plan that includes high throughput amplicon sequencing, metagenomics, and quantitative PCR along with traditional culturing and chemical approaches that have been well established for potable water distribution systems. The approach will identify key factors, such as: level of assimilable organic carbon, presence of disinfectant, type of disinfectant, water age, and temperature that influence microbial constituents of emerging concern in reclaimed water distribution systems and thus inform future management guidelines. It has only recently been established that microbial regrowth in reclaimed water distribution systems is the primary source of waterborne disease in developed countries; however, regrowth in reclaimed water distribution systems is relatively uncharacterized, despite reasonable expectations and preliminary results that suggest even greater potential for problems due to higher levels of nutrients, source water containing microbial constituents of emerging concern, and nuances of reclaimed water distribution systems operation in water stressed regions. Left unaddressed, these concerns will impede the direct use of reclaimed water and call into question existing reclaimed water distribution systems practices. The proposed effort will address key knowledge gaps and support rationally engineered water reuse systems that allow the benefits of reclaimed water to be fully realized, while protecting public health. The proposed work will achieve the following Objectives: O1: Conduct a lab study to examine the interplay between water treatment, nutrient level, disinfectant type, distribution system design/operation, and temperature in selecting for microbial regrowth and microbial constituents of emerging concern occurrence in reclaimed water distribution systems; O2: Conduct a field survey comparing the microbiome composition and microbial constituents of emerging concern occurrence of paired reclaimed water distribution systems and potable water distribution systems as a function of kind of treatment, nutrient levels, secondary disinfectant type and dose, distribution system materials, and water age; and, O3: Based on O1 and O2, identify engineering practices that are promising for minimizing the occurrence of microbial constituents of emerging concern in reclaimed water distribution systems to inform future design, management, and standards for safe application of reclaimed water for non-potable and potable reuse.
