Abstract: A process for separating ash particles from an aqueous slurry containing a mixture of regenerated adsorbent (e.g., carbon) and ash particles includes the steps of settling the slurry to produce a solid phase including the mixture of adsorbent and ash particles and a supernatant or a clarified aqueous phase. After separation of the aqueous phase, a slurry of the solid phase is diluted with water and a dispersing agent for promoting suspension of the ash particles and an anionic polymer for promoting settling of the adsorbent particles are added. The thus-treated, dilute slurry is settled to produce an aqueous phase containing primarily suspended ash particles and a solid phase including carbon particles. After separation, the solid phase can be returned to a wastewater treatment system.

Abstract: Suspended ash in wastewater is efficiently concentrated and removed by mixing the ash suspension with thermally conditioned sludge. The solids in the resulting ash/sludge mixture are easily settled and dewatered by conventional means.