Dew
Like most scientists, I wouldn't risk my reputation rendering opinions on an emerging technology that has a long way to go to demonstrate field viability. I did not read the entire article but one thing that would concern me besides maintenance costs is that the 2nd step requires treatment using electrodes. This may look good in a lab where the electrode placement and geology are probably simplified (uniform sands or such). This might suggest that the process can be implemented in-situ.. In most settings the geology is more complex such that the 2nd step (and probably the 1st step as well) are better implemented ex-situ rather than in place. So groundwater would have to be treated by pumping it to a treatment cell where the two treatment steps would be conducted. Depending on how prolific an aquifer is, the scale up to handle a large volume of water can get expensive. Also, typically for most chemicals I've dealt with the treatment effort might have to exchange 50 to 100 times the calculated volume of contaminated pore water. This is necessary because contaminants are sorbed onto the aquifer matrix and then desorb and diffuse out of pores as the concentration gradients are reduced by the remedial action.. In the case of PFAS and PFOS I'm not sure whether this volume of treated would be greater or less. I don't recall having seen a lot of data on the Koc and Kow partitioning coefficients that might provide an Idea as to how difficult it will be to desorb PFAS/PFOS contaminants (i.e., how long a remedial effort would need to run). To be frank, I'm entering retirement and have not looked for this info. My best guess is that it will be 5 to 10 years before such pilot technologies are being proved at any scale.
This class of chemicals will have a very low maximum contaminant level (MCL) so typically more effort is required to achieve the standard. A good point of use treatment system that is small enough to fit under the sink and be maintained by the average home owner would be a huge seller. I'm sure 3M and others are working to develop such systems for water treatment plants.
Sorry about the lengthy discussions but I wanted to hit on some of the variables that will play a role in this evaluation. As I think I said before, the tendency in the business is to underestimate the time to achieve remediation goals and to underestimate final costs.
FL
