SLUDGE TREATMENT METHOD AND ORGANIC WASTE WATER TREATMENT METHOD INCLUDING THE METHOD

摘要

PURPOSE: To separate and recover a phosphorus component efficiently in a short time by heating sludge at specific temp. for a specific time. CONSTITUTION: In a phosphorus discharge tank 3, sludge is heated at 60-90 deg.C for 10-120 min by a heating means 9 to discharge a phosphorus component in sludge to a liquid phase. When sludge is heated under this condition, the phosphorus component can be precipitated mainly as polyphosphoric acid. Whereupon, as compared with such a case that the phosphoric component is discharged as orthophosphoric acid or the like, the necessary amt. of a flocculant such as a metal salt or the like necessary for recovering the phosphorus component as a precipitate from a liquid phase is reduced. Since metal polyphosphate forms larger granular precipitated lumps as compared with metal phosphate, recovery treatment becomes easy. As a result, the phosphorus component contained in org. waste water can be separated and recovered in a small vol. liquid or solid state for a short time.