Project 5: Novel Filtration Devices for Arsenic Reduction

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ABSTRACT: PROJECT 5 In the US, 14% of Americans rely on private wells as their drinking water source. In NC, geogenic and anthropogenic contaminants (e.g., inorganic arsenic (iAs), manganese, chromium, and vanadium) infiltrate private wells, placing residents at risk for health outcomes (e.g., diabetes associated with iAs exposure). An estimated ~3 million individuals representing one-third of the population in NC drink water from private wells with iAs concentrations up to 800 µg/L. The US EPA and NC-DHHS recommend reverse osmosis membrane filtration and solid media to remove iAs from well water because these technologies require the fewest chemicals and steps to remove iAs and are easy to implement. However, two important challenges to these two technologies in this context are that both: (i) inadequately remove As(III) (i.e., the most hazardous iAs species), and (ii) produce iAs-enriched waste. Of the two technologies, membranes are best suited to treat groundwater because compared to solid media, they are more effective at removing As(III), are easier to operate, are more compact, and afford faster access to clean water. However, membrane systems allow iAs-enriched brines to re- enter into the water cycle and are not designed specifically to remove iAs and co-occurring contaminants (CCs). Arguably, the most valuable advantage solid media has over membranes is that the resulting iAs-enriched waste is easier to dispose. We hypothesize that an integrated membrane-sorbent system will remove iAs and CCs from groundwater with better efficacy than existing in-home water treatment systems, while minimizing iAs re-entry into the environment. Project 5 therefore aligns with the theme of the UNC-SRP Center, “Identifying novel methods to reduce iAs exposure and elucidating mechanisms underlying iAs- induced metabolic dysfunction with a vision for disease prevention” and addresses SRP Mandate 4 in using hypothesis-driven research to develop a product-oriented solution for communities affected by exposure to iAs and CCs. Project 5 will address research gaps to: (i) develop technologies that effectively remove As(III) from water without chemical pretreatment; (ii) optimize the ability of membranes to remove iAs, especially As(III), without compromising water productivity; (iii) develop sorbents to treat iAs-containing membrane brines; (iv) introduce the concept of removing geogenic and anthropogenic CCs (i.e., Mn(II), Cr, V) from waters in addition to the primary contaminant of concern (iAs); and (v) introduce biomedical metrics to assess performance of iAs membrane filtration systems. We will accomplish our goals with three specific aims: First, we will develop and optimize membranes to remove iAs and CCs from groundwater by combining polyamide, sulfonated poly(ether ether ketone) (sPEEK), and/or mixed-matrix chemistries; Second, we will optimize a polyethylenimine (PEI)- based granular sorbent for iAs and CCs removal from membrane brine; Third, we will deploy an integrated membrane-sorbent system prototype and evaluate it for performance stability in impacted NC communities.