Destruction Process Basics
Energy is the primary cost driver when it comes to destroying PFAS. In 2021, Enspired Solutions won an award from EPA and the Department of Defense for PFAS destruction and energy efficiency using our novel photo-activated reductive defluorination (PRD) technology. By using PRD, we can optimize both energy- and cost-efficiency for PFAS destruction.
One of the ways we achieve award-winning energy-efficiency is by taking advantage of the first-order kinetics of PRD chemistry. This means that the same amount of energy is required for each 10x decrease in PFAS mass regardless of whether you begin with a PFAS concentration of 10 ppm or 10 ppb (Figure 1). PRD efficiency is optimized when initial concentrations of PFAS are high and PFAS destruction targets are capped at two to three orders of magnitude (99-99.9%) reduction. Using this model, the ratio of PFAS mass destroyed per unit of applied energy remains high which translates to significantly lower energy costs.
In practice, high efficiency PFAS destruction using PRD is achieved using a process flow that incorporates PFAS separation & concentration in a recirculation loop with destruction (Figure 2). The process aims to convert high volume, low-PFAS-concentration system flow into low-volume, high-PFAS-concentration flow for maximum destruction efficiency.
The process components in Figure 2 are:
- System Flow (blue arrows). This is raw water that contains PFAS, such as groundwater, industrial or municipal wastewater, or landfill leachate.
- PFAS Separation & Concentration Unit. System flow enters this unit (System Influent) and PFAS is removed and concentrated by 2-3 orders of magnitude. Remaining water exits this unit (System Effluent). Examples of this technology are foam fractionation and membrane filtration.
- Destruction Loop (red arrows) and PFASigator™. Destruction-ready, concentrated PFAS from the Separation & Concentration Unit enters the PFASigator™, PFAS is destroyed to a site-specific target approximately equal to the PFAS concentration in System Influent (i.e., 2-3 orders of magnitude reduction), and the remaining solution is discharged back to the Separation & Concentration Unit.
Simple example metrics are provided in Figure 3 to illustrate the destruction process basics. Note that PFAS concentration in the System Effluent is controlled by the PFAS Separation & Concentration Unit.
Enspired Solutions can estimate site-specific PFAS destruction costs using the PFASigator™ and this process model by executing a benchtop treatability test on PFAS concentrate.