| 摘要 |
Provided is a technique which makes it possible to recover fine MAP particles which cannot be separated by a physical means such as a liquid cyclone so as to significantly improve a phosphorus recovery ratio from sludge. Proposed is a method for treating organic waste water or organic sludge including a phosphorus separation step in which by using MAP particles contained in anaerobically treated sludge obtained by anaerobically treating organic waste water or organic sludge as seed crystals, the MAP particles are grown by crystallizing and precipitating, as MAP, a phosphorus component dissolved in solid-liquid separation water returned from the subsequent sludge amount reduction step, followed by separation into the grown MAP particles and MAP depleted sludge, a pH adjustment step in which the pH of the MAP depleted sludge obtained by the separation in the phosphorus separation step is lowered to dissolve the MAP particles remaining in the MAP depleted sludge, thereby obtaining pH-adjusted sludge, and a sludge amount reduction step in which dewatered cake is obtained by concentrating and dewatering the pH-adjusted sludge and a part or the whole of solid-liquid separation water obtained by the concentration and dewatering is returned to the phosphorus separation step. |
