Research

I am broadly interested in water sustainability, which spans drinking water, wastewater, and natural aquatic environments. Specifically, my research takes a systems thinking approach to water quality and treatment that considers global drivers such as urbanization, climate change, biogeochemical cycles, sustainable engineering, and disruptive innovation. Examples include coupling laboratory experiments and life cycle assessment to evaluate the sustainability of novel approaches to drinking water treatment (e.g., innovative ion exchange treatment and regeneration) and wastewater management (e.g., urine source separation); using comprehensive laboratory, pilot, and field experiments to inform the design of urine source separation and treatment systems considering urine collection, nutrient recovery, pharmaceutical removal, and beneficial use; and coupling groundwater modeling, life cycle assessment, field data collection, and laboratory experiments to investigate the effects of sea-level rise and seawater intrusion on drinking water treatment. My contributions to these research areas and my future research interests are described below.

Many of my research projects that focus on drinking water treatment involve innovative applications of ion exchange, which have been supported by federal grants (e.g., EPA STAR grant, “Small, Safe, Sustainable (S3) Public Water Systems through Innovative Ion Exchange”) and industry partners (e.g., cash gifts from Orica Watercare, Jacobi Carbons, and EE&T). Ion exchange is a robust process that can selectively remove a wide range of chemical contaminants, can perform effectively under changing water chemistry, and can operate in different process and reactor configurations. My major contributions to the field of ion exchange are documented in 38 articles in refereed journals, which show comprehensive coverage of topics including:

  • Operation, design, and performance of magnetic ion exchange (MIEX) process;
  • Mechanism of natural organic matter removal by anion exchange resin;
  • Development of innovative combined ion exchange process for multi-contaminant removal;
  • Mathematical modeling of ion exchange reactors;
  • Ion exchange treatment of diverse water matrices including surface water, groundwater, membrane concentrate, wastewater, and landfill leachate;
  • Alternative approaches to ion exchange regeneration and concentrate management;
  • Secondary effects of ion exchange on corrosion potential of distribution systems and household plumbing.

My research on wastewater management has focused on the new field of urine source separation and treatment, which has been proposed as an alternative to conventional wastewater management because of its potential to conserve water and energy, recover nutrients for beneficial use, and protect ecological and human health from pharmaceutical micropollutants. My NSF CAREER award, “Sustainable Urine Processes through integration of Education and Research (SUPER),” is the centerpiece for numerous research activities on urine source separation that seek to fill key gaps in knowledge. Furthermore, I direct the most comprehensive research program in the U.S. that is investigating urine source separation, with research activities spanning urine chemistry, urinal and toilet function, nutrient recovery, pharmaceutical removal, life cycle impacts, fertilizer effectiveness and agricultural yield, and public perceptions. Major accomplishments and contributions include:

  • High impact publications including the first investigations of phosphorus removal from urine using anion exchange resin (Sendrowski and Boyer, 2013); phosphorus recovery potential of undiluted urine relative to diluted and mixed urine and end-of-pipe waste streams (O’Neal and Boyer, 2013); in situ urine treatment in waterless urinals using ion exchange (Boyer et al., 2014); and selective separation of pharmaceuticals and nutrients in urine using anion exchange resins (Landry and Boyer, 2013; Landry et al., 2015).
  • High visibility presentations at international and national meetings sponsored by the International Water Association (IWA), Water Environment Federation (WEF), American Chemical Society (ACS), and the Association of Environmental Engineering and Science Professors (AEESP), and invited lectures at nationally recognized environmental engineering programs including Arizona State University, Georgia Institute of Technology, University of Minnesota, and University of South Florida.
  • Productive mentoring of graduate and undergraduate students including one Ph.D. student graduated (Stephanie Ishii), three current Ph.D. students (Kelly Landry, Avni Solanki, Neha Jagtap), one master’s thesis student graduated (Jeremy O’Neal), and experience for 10 undergraduate students.
  • Additional federal funding including Co-PI on EPA Center for Water Research on National Priorities Related to a Systems View of Nutrient Management, and PI on two EPA P3 grants in which student teams conducted research and designed urine treatment systems.

My research interests in the natural environment include aquatic natural organic matter and freshwater–seawater interactions. Aquatic natural organic matter is ubiquitous in all aqueous environments and has major impacts on ecosystem function and engineered processes. A review article that we published (Ishii and Boyer, 2012. Environmental Science & Technology) was the first comprehensive meta-analysis on the behavior of reoccurring fluorophores (i.e., fluorescent components of natural organic matter) in natural and engineered aqueous systems and broadly contributes to fluorescence characterization of organic compounds. The immediate impact of this article was evident through invitation to present research at International Workshop on Organic Matter Spectroscopy 2013 (WOMS 2013) in La Garde City, France, 16–19 July 2013 and continued impact evident by Highly Cited Paper status on Web of Science. Also related to the natural environment is a multidisciplinary effort that I led investigating the impacts of coastal urbanization and sea-level change on groundwater composition and drinking water treatment. Results showed that seawater intrusion induced by sea-level rise can have profound impacts on drinking water treatment such as elevated formation of disinfection byproducts during chlorination. These results have generated several presentations for national conferences and several publications.

In summary, my research program is advancing the broad field of water sustainability, with emphasis on ion exchange treatment, urine source separation, characterization of aquatic natural organic matter, and freshwater–seawater interactions, through competitive federal grants (e.g., NSF and EPA), national and international presentations, and publications in high-impact journals such as Water Research [Impact factor 5.991], Environmental Science & Technology [Impact factor 5.393], and h-index (Google Scholar) of 20.

My research experiences described here have convinced me that a paradigm shift is needed that focuses on resource recovery (e.g., water, energy, nutrients, metals) and holistic management of resources and contaminants. To advance this paradigm shift, a critical question that remains to be answered is at what spatial scale do we implement novel technologies and engineering solutions? For example, do we take a fully centralized approach such as being proposed for direct potable reuse or individual decentralized systems such as proposed for urine source separation? Accordingly, my research vision over the next 2–5 years is to build a research program to answer the question of technology implementation scale, and other pressing challenges, through a combination of use-inspired research, modeling approaches, and testbed installations. Specifically, I plan to build a urine source separation testbed to evaluate different unit processes for nutrient recovery and contaminant removal under realistic operating conditions. This will also generate primary data for calibrating new process models and life cycle assessment models. Together, the testbed installation, process models, and life cycle models will provide new insights to advance the implementation of urine source separation and further the paradigm shift of resource recovery.