The process design was built on the state-of-the-art understanding of the complementary capabilities of the two modules: 1) UV/S is highly effective for defluorinating long-chain PFAS that EO could not defluorinate to 100%; 2) EO is highly effective in mineralizing short-chain PFAS and H-rich TPs from UV/S treatment, both of which are recalcitrant under UV/S; and 3) UV/S treatment effectively suppressed foaming that could cause operational issues for EO. Moreover, both UV/S and EO exhibited high energy efficiency in treating AFFF with limited dilution. EO also enabled the near-complete removal of TOC in AFFF. All reactor components are commercially viable at full-scale. The integration only requires conveying the treated effluents without retrofitting the reaction units. We expect this treatment strategy to be also effective toward novel PFAS structures in various practical scenarios under ambient conditions. Lastly, we emphasize that UV/S-EO was developed for the non-potable treatment of obsolete AFFF stockpiles and fire-fighting system cleaning solutions. Therefore, the concern about the disinfection byproducts, which are only regulated in the drinking water supply, should not constrain the improvement and deployment of the process. Besides, technologies for removing halogenated byproducts and oxyanions are widely available and can be adopted as post-treatment add-ons. We are developing various engineering processes with pre-and post-treatment that can further expand the application scope of UV/S-EO in even more challenging water matrices.