Under this agreement, the recipient will demonstrate hydrophobic ION-pairing in a pilot-scale granular activated carbon system to treat per- and polyfluoroalkyl substances contaminated groundwater

This Cooperative Agreement award from the U.S. Department of the Interior's Bureau of Reclamation, under the SECURE Water Act - Research Agreements program (CFDA 15.560), provides $311,880.59 to the New Jersey Institute of Technology (NJIT) to demonstrate the use of hydrophobic ion-pairing to enhance the removal of per- and polyfluoroalkyl substances (PFAS) from contaminated groundwater through a pilot-scale granular activated carbon (GAC) treatment system.

The project aims to optimize the dosage and operating conditions of the hydrophobic ion-pairing pre-treatment to maximize GAC performance for PFAS removal. It will also assess the impact of this pre-treatment on the removal of co-contaminants like volatile organic compounds and chlorinated solvents. The pilot-scale testing will take place over a 2-year period from September 2023 to September 2025 to help inform the design and operational parameters for full-scale PFAS treatment systems using this approach.

Pilot-scale testing of the approach will help to optimize the type, dosage, and operating condition of the system for the removal of per- and polyfluoroalkyl substances mixtures in field conditions. The full proposal, enhancing the removal of hydrophilic per- and polyfluoroalkyl substances by granular activated carbon using hydrophobic ION-pairing as pre-treatment, submitted in response to notice of funding opportunity announcement no. R22AS00316, desalination and water purification research program pitch to pilot, is incorporated herein via reference. IT includes the detailed technical approach, hypotheses, key personnel, and other details regarding the project.5.1. Approved scope of work. Under this agreement, the recipient shall perform the following tasks:5.1.1 construction of pilot-scale columns. Suffolk county water authority has conducted pilot testing of granular activated carbon in the past for the removal of volatile organic compound using eight columns of 12 feet in length receiving a flow rate of 1.15 gallons per minute. The columns will receive flow under gravity from an elevated overhead constant head tank through a solenoid valve. Digital gauges will be installed at the inlet to measure flow through the columns and to calculate bed volumes of breakthrough. Chemical injection pump and a flash mixer will be introduced at the inlet of the granular activated carbon pilot column to dose hydrophobic ION-pairing additive. Control columns without hydrophobic ION-pairing additives will be tested in parallel to compare the performance of the proposed pre-treatment. Six of the columns will be utilized for the pilot study, with two columns serving as back up for any column failures.5.1.2 effect of concentration and dosing type of hydrophobic ION-pairing agent. Different dosing of hydrophobic ION-pairing agent will be tested for dosing optimization. The project team will vary the dosing concentration to observe the differences in per- and polyfluoroalkyl substances breakthrough from columns compared to no hydrophobic ION-pairing pre-treatment. Four pilot columns will be utilized for this purpose. Influent and effluent samples will be collected once a week over the pilot testing period. Samples will be analyzed for per- and polyfluoroalkyl substances and cetyltrimethylammonium chloride to observe breakthrough. Cetyltrimethylammonium chloride breakthrough bed volumes will be observed and used for the second phase this task to test dosing type. This task will identify ideal dosing of cetyltrimethylammonium chloride to maximize granular activated carbon performance to remove per- and polyfluoroalkyl substances. Phase 2 of this task will assess the application of temporary VS. Continuous dosing type on the performance of granular activated carbon columns to remove both hydrophilic and hydrophobic per- and polyfluoroalkyl substances. The improvement in breakthrough bed volumes will be used to calculate the increase in carbon life and reduction in carbon changeout frequency for per- and polyfluoroalkyl substance treatment.5.1.3 effect of hydrophobic ION-pairing pre-treatment on the removal of CO-contaminants. In addition to per- and polyfluoroalkyl substances, the optimized columns will be utilized to assess the removal of other CO-contaminants. The project team will analyze for volatile organic compound and chlorinated solvents using established environmental protection agency methods by sending samples to certified commercial laboratories. The outcome of this task will be to understand how the proposed pre-treatment affect the performance of granular activated carbon to remove other principle organic contaminants present in groundwater systems.