Patent attributes
A method of treating, in wastewater purification, sludge containing organic matter, divalent iron and phosphorus, in whichthe sludge that is treated is made to contain dissolved iron and phosphorus at a molar ratio Fe:P of above 1:1,the sludge is treated at 0–100° C. with an acid at a pH of 1–5 for dissolution of divalent iron and phosphorus from the sludge,the sludge is supplied with an oxidizer selected from hydrogen peroxide and percompounds, wherein divalent iron is oxidized by Fenton's reaction to trivalent iron, and(i) trivalent iron is precipitated as trivalent iron phosphate(ii) free radicals with a deodorization and sanitation effect are formed by Fenton's reaction,the sludge is then dewatered at a pH of at most 7, andthe aqueous solution obtained in dewatering is recirculated to the wastewater purification.
