Methods and systems of photosensitizer recovery for improved pfas destruction

A PFAS destruction system comprising:

• an influent piping system configured to supply influent comprising water including PFAS to the system;
• one or more supply tanks of fresh reactants comprising photosensitizer, sulfite salt and base, the one or more supply tanks configured to supply fresh reactants to the influent before or within the photoreactor to form a treatment solution;
• a UV photoreactor configured to receive influent from the influent piping system, the photoreactor comprising a plurality of UV light sources configured to direct UV light onto the treatment solution to destroy the PFAS and form a treated effluent;
• a selective membrane configured to receive the treated effluent and to form membrane reject and membrane permeate;
• a membrane permeate piping system configured to convey the membrane permeate to post processing systems or to discharge;
• and
• a membrane reject piping system configured to convey the membrane reject to a location upstream of the UV photoreactor or into the photoreactor to combine the membrane reject with influent.