2003 年 16 巻 1 号 p. 400-404
A beach-top study of phosphorus-recoveuing technology from ash or charcoal associated with wastewater treatment sludge was conducted by adding sulfuric acjd to ashes. When the pH of the ash fell below 1-2, phosphous and various heavy metals in the ash or charcoal were extracted. Phosphorus was recovered with addition of alkalis to adjust the pH 4.0 via filtration. This phosphorus was mainly made of aluminum phosphate. When alkalis wete added to adjust the pH to 10, the recovery of various heavy metals was observed In addition, disposal of the remaining solution, which consists of a relatively low concentration of salts, has been found to be useful as acid-treating water The charcoal free from phosphorus and heavy metals showed lower ash component and higher methylen blue adsorption ability.