Solutions to Water Issues on Navajo Nation: Groundwater Treatment and Water Reuse

Abstract

Water scarcity and groundwater contamination continue to be significant challenges for Indigenous communities in the United States, especially within the Navajo Nation. There, legacies of mining, underinvestment in infrastructure, geographic isolation, and water injustice have exacerbated water insecurity. Finding a solution to provide clean, economically safe drinking water to the approximately 40,000 residents of the Navajo Nation without modern water access exemplifies a "wicked problem." This dissertation seeks to shed light on ways to help mitigate the “wicked” water issue in the Navajo Nation. It explores site-specific and technologically feasible solutions to address groundwater contamination and wastewater reuse opportunities in the Navajo Nation through applied environmental engineering and membrane-based treatment processes. This dissertation, structured into one literature review chapter and three research chapters, begins with an assessment of groundwater chemistry in selected water sources across the Navajo Nation (Chapter 2). By utilizing geochemical modeling, the study characterizes the profiles of arsenic and uranium contaminants while evaluating practical remediation technologies. This analysis incorporates hazardous waste management and economic feasibility, providing recommendations for the implementation of localized treatment systems. Chapter three investigates uranium rejection using commercially available nanofiltration membranes in environmentally relevant conditions. Experimental results illuminate fundamental mechanisms of uranium rejection and illustrate how ionic composition impacts uranium speciation, adsorption phenomena, and membrane selectivity. This provides critical insights into the physicochemical interactions that govern uranium removal in realistic water matrices. Chapter four examines advanced treatment of secondary wastewater effluent from facultative lagoons through integrated microfiltration and nanofiltration processes. Comprehensive water quality and microbiological analyses show that nanofiltration-treated effluent meets federal and state agricultural reuse standards. The study demonstrates the effectiveness of a microfiltration and nanofiltration treatment system in eliminating pathogens, regulated contaminants, and contaminants of emerging concern. The findings presented in this dissertation provide an integrated framework for enhancing water access and quality in the Navajo Nation through evidence-based treatment selection, cost-effective engineering design, and alignment with local conditions. This research contributes to the advancement of sustainable water infrastructure and environmental justice for the Navajo Nation and other underserved communities facing water challenges globally.