Designing POE Water Treatment Systems for PFAS Removal

Guidelines

A point-of-entry (POE) water treatment system treats all of the water entering your location from the main water line before the water enters individual supply lines for individual faucets and other internal feeds.

When designing a POE system for removing perfluoroalkyl substances (PFASs), engineering teams should do the following:

  • Assume a peak flow rate per household of 7.5 gpm (30 LPM)
  • Design the POE device for a specific flowrate of 2.5 to 5 gpm/ft3 of resin (20 to 40 BV/h)
  • Use a 10" x 54" (10 inches diameter x 54 inches sidewall) lined FRP tank containing
  • Install 1.5ft3 (42 L) of Purofine® PFA694E resin for adequate treatment.
Prefiltration is needed for control of influent suspended solids and chlorine or similar oxidants since these will compromise the performance of the resin and system.

Conservative capacity based on treating typical drinking water will be approximately 10,000 bed volumes or about 110,000 gallons based on 1.5 ft3 of resin. Based on an estimated consumption of 300 gallons per day (1.1 m3) the resin would be changed out annually. 

Backwashing of the resin is only recommended at the first install. Once in service, no further backwashing should be performed as it compromises the expected capacity of the resin. Good prefiltration is needed to minimize influx of suspended matter.

Consider installing two resin tanks in series if greater assurance is needed for reducing to non-detect levels, and analyze samples taken periodically after the first and second tanks.

Please note that performance will depend on the actual system design used by the OEM.*

*Note on Guidelines
These guidelines apply only to Purofine® PFA694E resin, which is designed specifically for PFAS (or PFC) removal with short contact times. These guidelines do not apply for standard ion exchange resins. Purolite reserves the right to revise these guidelines if the water to be treated is atypical. Please consults your local Purolite office for more guidance before design. No performance guarantee can be given as the performance of the treatment system depends on the design of the entire treatment system over which Purolite has no control.