NATURE-BASED SOLUTIONS FOR INDIRECT POTABLE REUSE (IPR) OF EFFLUENT WATER TO SUPPORT WATER SUPPLIES SEPA www.epa.gov/research science in ACTION INNOVATIVE RESEARCH FOR A SUSTAINABLE FUTURE Background Water scarcity is an ongoing concern throughout the nation. The reuse of safe treated effluent can augment increasing water supply demands, provide habitat benefits, and protect receiving water quality. This has led municipalities and states to move toward approaches that incorporate reuse to supplement existing water sources. Regardless of the degree of treatment that a water reclamation facility applies to ensure that the water is safe, clean, and healthy, direct reuse of treated effluent can be difficult for communities to approve. Indirect potable reuse (IPR) offers the advantage of an "environmental buffer" between the point of effluent discharge and entry into the potable water supply. Moving treated effluent through a wetland, stream, or floodplain can provide value added habitat, water quality improvements, and a vari ety of other ecosystem services that nature- based solutions provide. Evaluation of these practices with defensible scientific research will better support decisions related to nature-based solutions and indirect potable reuse. In Oklahoma and many regions with limited water supplies, novel applications of water reuse are being developed and implemented. Nature-based solutions for water reuse can take advantage of the biological and physical processes in natural or modified systems like wetlands, streams, and floodplains that receive treated effluent. Some of these systems are designed and implemented to take advantage of the natural processes that can decrease our dependence on costly single purpose grey infrastructure. The benefits of additional water and desire to support sustainable solutions are clear. Research and evaluation of the effects of nature-based solutions, like the application of wetland systems in IPR, will support safe and sustainable water reuse decisions across the nation. Existing outfall at the Norman site 2023. Potential constructed wetland site for water quality at the Norman Water Reclamation Facility. Source: Bureau of Reclamation Like many municipalities, the City of Norman (City) anticipates additional water needs to support the city's growing demands, which are expected to double over the next 40 years. Today, treated municipal effluent is discharged to a nearby river without supporting the city's potable water system. However, with the addition of advanced treatment and wetlands to receive effluent, this water may be permitted to supplement potable water supply source streams and reservoirs. Improved understanding of the interaction between surface water and groundwater as well as chemical transformations of nutrients and other pollutants in treated effluent conveyed to these nature-based environmental buffers can help improve decision-making and manage any potential risks and benefits. 1 U.S. Environmental Protection Agency Office of Research and Development ------- Science to Support Solutions To move forward, a new research effort has started in collaboration with the City of Norman, USEPA's Office of Research and Development (ORD) and USEPA Region 6 to examine the use of wetland construction in IPR and determine the effects on water quality at the Norman Water Reclamation Facility in Norman, OK. The research done at this site will help demonstrate how wetlands and other floodplain restoration activities augmented with treated effluent can support the protection of groundwater, surface water, and help meet designated use requirements. This research will evaluate approaches of effluent water reuse with the intention to support practical and applicable permitting and decision-making. The research will include evaluation of hydrology, chemistry, and biogeochemical processes that are critical to protect water quality. ORD and the City have partnered to work at the City of Norman's floodplain property adjacent to the water reclamation facility to evaluate the effects of a planned wetland that will be designed to receive treated effluent that could be used for indirect potable reuse. This research will leverage an ongoing, multi- agency feasibility and pilot study of a constructed wetland that the City intends to install on its property as one part of a solution to water scarcity in the region. Nature-based solutions, particularly wetlands as environmental buffers in floodplains, may be beneficial to support water quality and support greater habitat. Currently, case studies and scientific data on the effects of these nature-based solutions are scarce and guidance for permit writers or decision makers is limited. Answering questions about the effects of these systems on the surrounding water bodies including receiving waters in the ground and surface Contacts Ken Forshay Ph.D. Research Ecologist and ORD Project Lead. Robert S. Kerr Environmental Research Center. Ada, OK 580- 436-8912. Forshav.Ken@epa.gov Jacob Oliveira Environmental Engineer ORD. Robert S. Kerr Enviromnental Research Center. are critical to ensure the best outcomes of novel nature-based solutions like constructed wetlands. The intent of this research effort includes evaluation of groundwater and surface water interactions, and the influence of the practice on water quality. Also included is the evaluation of the ecosystem services provided by novel water reuse management practices. ORD has installed several monitoring wells and surface water sites to evaluate the water chemistry, soil, and sediment before and after a pilot scale wetland installation. By collaborating with motivated communities, like the City of Norman, everyone can better understand the potential tradeoffs and ultimate benefits that these nature-based systems provide. This collaborative effort not only allows us to realize the potential benefit to improve water quality and enhance ecosystem services in this community but share research results with a larger body of practitioners interested in applying similar approaches. USEPA and the City of Norman are developing this research collaboratively to design experiments and monitoring that are meaningful to stakeholders and to identify additional effluent treatment options that may expand accessibility of precious water resources. Progress ORD and the City of Norman have established a Memorandum of Understanding to carry out this work and ORD is supporting part of this work in the Safe and Sustainable Water Research program. More importantly, project partners are working together to develop collaborative research and establish a site where the potential water quality effects of nature- based solutions to water scarcity will provide important scientific evidence about the benefits of water reuse and a nature-based constructed wetland solution to improve water storage and availability in times of increased water demand. Christopher A. Mattingly, P.E., Utilities Director, City of Norman. Norman, OK Juanita Huff Ph.D. US EPA Region 6 Technical Lead Suzanna Perea US EPA Region 6 Collaborator EPA Publication # EPA/600/S-24/227 2 U.S. Environmental Protection Agency Office of Research and Development ------- U.S. Environmental Protection Agency Office of Research and Development ------- |