EREF Science Session 4 – Rock Solid: Evaluating Solidification of PFAS in RO Concentrate





  • Paul Ruehl, U.S. Environmental Remediation Specialist, LafargeHolcim
  • Ryan Schipper, PE, Senior Engineer, Golder Associates
  • Patrick Stanford, General Manager, Rochem Americas, Inc.

Moderator: Bryan Staley, PhD, PE, President and CEO, Environmental Research & Education Foundation (EREF)

Per- and polyfluoroalkyl substances (PFAS) present a challenge for typical treatment strategies and technologies due to their strong chemical bonds and our limited knowledge of the nearly 5,000 types of PFAS. As a result of these strong bonds and their resistance to breaking down, they have earned the name “forever chemicals”. Given this, only a few conventional treatment strategies (e.g. reverse osmosis) have demonstrated the ability to provide significant removal of PFAS from landfill leachate. Thus far, such technologies serve to concentrate rather than destroy PFAS, which leaves a residual that must be managed. One strategy that is currently being evaluated to deal with residuals containing PFAS concentrations is called solidification/stabilization. This technique, which has commonly been used in the power industry to deal with flue gas residuals, has been adapted and is being evaluated as a way to deal with PFAS concentrated residuals from leachate treatment.

How does this strategy work alongside existing technologies and what do the experts have to say about them? During this session, waste industry experts will discuss the following:

  • Typical treatment technologies and residual management options
  • Use of reverse osmosis as treatment of PFAS in leachate
  • Residual solidification/stabilization
  • Effectiveness of these treatments
  • Where additional science and research are needed to employ these strategies