In water reclamation systems, management and disposal of reverse osmosis concentrate (ROC) is a growing challenge, especially for inland communities that lack ocean disposal options

The U.S. Department of the Interior Bureau of Reclamation awarded a $557,406.76 Cooperative Agreement to William Marsh Rice University under the SECURE Water Act - Research Agreements program (CFDA 15.560). The goal of this 18-month project, with an estimated completion date of September 2025, is to further evaluate the effectiveness of boron nitride-based photocatalytic materials for the destruction of per- and polyfluoroalkyl substances (PFAS) in brackish groundwater and reverse osmosis concentrate (ROC) streams. Key objectives include: (1) assessing the photocatalytic performance of the materials in treating PFAS and other contaminants, (2) scaling up and optimizing the technology for pilot-scale ROC post-treatment to improve energy efficiency, and (3) evaluating the economic and environmental impacts of using the technology for brackish water pretreatment versus ROC post-treatment. This research aims to advance innovative solutions for addressing the growing challenge of managing PFAS-contaminated water sources, particularly for inland communities without ocean disposal options.

ROC typically represents 25% of the feed water flow and contains high concentrations of organic and inorganic contaminants, which could contribute to adverse impacts at the point of discharge. In particular, nonbiodegradable organic compounds, like per- and poly-fluoroalkyl substances (PFAS), are concentrated in residual streams. PFAS bioaccumulate in humans and wildlife, and have been linked to developmental and reproductive problems, liver heart damage, and cancer. As a result, PFAS concentrations in ROC typically exceed the current usepas drinking water health advisory levels of 0.004 PPT for perfluorooctanoic acid (pfoa) and 0.02 PPT for perfluorooctane sulfonic acid (pfos), the two predominant PFAS chemicals. This highlights the need for technology that can destroy PFAS in RO-based water reclamation systems.to address this problem, the wong group at rice university have been developing boron nitride (BN)-based materials that have excellent potential for low-cost, chemical-free PFAS destruction with due to their ability to photocatalytically degrade PFAS in water matrices relevant to brackish water, including salinity (2 m nacl) and dissolved organic carbon (10 MG-c l humic acid). The wong groups BN-based materials were successful in treating PFAS-contaminated brackish groundwater ( 420 NG l pfoa and 6000 MG l total dissolved solids (TDS)), provided from the US bureau of reclamations (usbr) brackish groundwater national desalination research facility (bgndrf) in new mexico (https: WWW.usbr.GOV research bgndrf water.html). This proposed approach for the destruction of PFAS using BN-based photocatalysts was further validated at the semipilot-scale with a 4.2 gallon volume photo-CAT reactor equipped with 875-w submersible vacuum-ultraviolet (VUV) lamps operated in batch mode. This unit, on loan as in-kind support from purific waters INC., also has flow-through capabilities. The objectives of this proposal are to (1) further evaluate the photocatalytic activities of BN-based materials in the treatment of PFAS and CO-contaminants in brackish groundwater and ROC streams, (2) extend and optimize the ROC post-treatment capabilities to the pilot-scale using the photo-CAT reactor to improve energy efficiency for water reclamation and (3) pretreat brackish water for PFAS at the pilot scale to determine cost effectiveness and energy efficiency, and compare to the economics of ROC post-treatment.furthermore, the success of the study will be measured by (1) the extent to which dominant PFAS (i.e. pfoa, pfos, and perfluorohexane sulfonic acid pfhxs) is destroyed in contaminated brackish groundwater and ROC streams at the bgndrf, (2) determining the energy efficiency of a minimum of one full month of continuous operations in pilot-scale experiments with flow rate of 1-10 gallons per minute to pretreat brackish water using equipment provided by purifics water INC. And evaluate the levelized cost of water (LCW), and (3) comparing to LCW from a similarly conducted post-treatment of ROC pilot. This limited-scope proposal is expected to last 18 months, the estimated completion is september 2025.the proposed project will address all six of the objectives in this nofo through the (i) development of an innovative technology for pretreatment of brackish groundwater or posttreatment of ROC (nofo objectives #2, #3, and #4), (II) destruction of PFAS and other contaminants of concern (nofo objectives #6), and (III) evaluation of economic and environmental impacts for treated water (nofo objectives #1 and #5).