Ways De Nora is working to tackle PFAS

July 5, 2022

What are PFAS?

Per- and Polyfluoroalkyl Substances (PFAS) are man-made chemicals that do not break down easily in the environment due to the highly resilient carbon-fluorine bond (the reason they are known as forever chemicals”). PFAS are known for having adverse effects on human health, ranging from reproductive issues and developmental delays to an increased risk of cancer.

What is the biggest treatment challenge for PFAS in the US? 

PFAS presence in soil and groundwater has created challenges for water utilities whose first mission is to provide clean drinking water for their constituents. Since PFAS research is still in the infancy stages, federal guidance is limited and local regulations vary from state to state, with the list of identified PFAS compounds continuously evolving. Utilities are challenged with having the proper equipment in place to treat for these toxic chemicals, which requires significant capital expense – a daunting task especially in areas where access to critical funding is already limited. 

How do I know what the best available technology type is for my application?

To identify the best solution for an individual application, a water analysis is necessary to get a complete profile of the water intended to be treated. A solution is built around that water profile, providing either the optimal removal, lowest capex or lowest opex. Piloting is available from De Nora to validate the performance before going full scale.

What information do you need to determine the best solution?

Part of the water profile should include space limitations, a list of other technologies on site, how much water needs to be filtered now, and how much in the future. These details will help ensure equipment is sized correctly and needs are met.

Which solutions does De Nora offer and how do they work?

De Nora will offer granular activated carbon (GAC), ion exchange (IX) and regenerable IX that is in pilot stages and paired with electrochemical advanced oxidation processes (EAOP) technology.

What is EAOP?

EAOP is a specialty coded electrode that acts as a reactor. When put into a solution, it breaks the carbon-fluorine (C-F) bonds of PFAS and removes them from the solution. In a drinking water scenario with regenerable IX, EAOP is part of the service for the regeneration of that media. The process would pass a non-chemical solution over the IX that concentrates the PFAS, which is then put through the EAOP for destruction. Once complete, the IX media bed is back up to full operation.

What kind of maintenance is required for the different solutions?

The maintenance required for De Nora tanks is unique - they are designed to be fully serviceable from outside the tank without the need for a confined space permit or extra personnel to be on site to do the service. All parts can be exchanged or serviced from outside the tank, including the inlet pipe, the underdrains, and all of the sample ports.

How easy are they to maintain – is there a master schedule of periodic activities?

Media life is very subjective and comes down to budget and water profile. Smaller systems require exchange more frequently, with a lower upfront capex and higher opex. For users with limited available down time, changeout frequencies can be extended by increasing size with more media in the vessel itself.

How long does the GAC or IX resin last? How does single use life compare to regenerable resin?

As of right now, the primary disposal method has been incineration for both GAC and IX.

How does De Nora recommend disposing the spent GAC or IX resin?

Following the recent ban on PFAS incineration by the Department of Defense, De Nora will speed up piloting the regenerative IX that uses EAOP technology to destroy PFAS from reject streams. It has the potential to change the future of the treatment industry.

Nick Armstrong, De Nora Water Technologies, global product manager