Abstract: Regenerated adsorbent particles, such as activated carbon, are recovered from a wet oxidation-regenerated mixed liquor sludge from a wastewater treatment system by diluting and settling a blowdown slurry from the wet oxidation reactor to obtain a first aqueous phase containing primarily regenerated adsorbent particles and fine ash particles and a first solids phase containing primarily grit particles. The first aqueous phase is combined with a portion of the regenerated adsorbent particle slurry withdrawn from the upper portion of the wet oxidation reactor and, after treatment with a dispersing agent and then an anionic flocculating agent, the resulting mixture is settled to obtain a second aqueous phase containing primarily fine ash particles and a second solids phase containing primarily regenerated adsorbent particles.