OCWD taps 374Water for SCWO pilot to destroy PFAS-laden ion exchange resin

OCWD taps 374Water for SCWO pilot to destroy PFAS-laden ion exchange resinFacing the future disposal of 45,000 cubic feet of spent resin annually across 68 treatment plants, the Californian utility is exploring Supercritical Water Oxidation as an alternative to incineration and landfilling.

The OCWD Water Issues Committee advanced a $135,000 agreement with 374Water for pilot testing.

A 55-gallon sample of spent IX resin will be shipped to 374Water's SCWO facility in Orlando, Florida.

The utility is proactively seeking alternatives to incineration due to potential cost increases, air emission regulations, and future RCRA/CERCLA hazardous waste designations for PFAS.

The pilot will yield a techno-economic analysis to help OCWD ascertain potential costs for adopting SCWO disposal.

The Orange County Water District (OCWD) is advancing a pilot project to test the destruction of PFAS-laden spent ion exchange (IX) resin using Supercritical Water Oxidation (SCWO). During its March 11, 2026, meeting, the utility's Water Issues Committee unanimously approved a $135,000 professional services agreement with 374Water to conduct the testing. The pilot aims to evaluate SCWO as a viable, long-term alternative to conventional disposal methods like incineration or landfilling. At full buildout, OCWD estimates that 68 local treatment plants will generate over 45,000 cubic feet of spent IX resin annually as they remove PFAS from groundwater supplies. Currently, spent resin is transported offsite for destruction by the resin provider. However, OCWD staff noted in a project report that these disposal options may face future logistical challenges and cost increases due to air emissions regulations, issues with co-contaminants such as radionuclides, and the potential future designation of PFAS as hazardous substances under CERCLA or hazardous wastes under RCRA. SCWO, a physical-thermal treatment technology, utilizes water at high temperatures and pressures to convert complex organic materials into benign end products like nitrogen, water, carbon dioxide, and mineral salts. Under the agreement, a 55-gallon sample of spent IX resin will be retrieved from an OCWD groundwater producer and shipped to 374Water's 6-ton-per-day pilot facility, located at the City of Orlando's wastewater treatment plant in Florida. The testing will be conducted in phases, starting with resin characterization and the development of an influent feedstock slurry recipe. The slurry will then be processed through the SCWO unit. Following the destruction process, 374Water will analyze the liquid, air, and solid matrices to evaluate PFAS removal efficiency. The company will also prepare a techno-economic summary for IX media destruction via SCWO, factoring in dilution requirements and any necessary pre-treatment, which will allow OCWD to ascertain the potential costs of the disposal method. The $135,000 budget includes $120,500 for the scope of work—of which $96,000 is allocated for third-party laboratory analysis—and a $14,500 contingency for potential additional shipping and analytical costs.