| 摘要 |
PROBLEM TO BE SOLVED: To provide treated ash of a pH suitable for effective use while suppressing an increase in treatment cost of sludge incineration ash.SOLUTION: A method for treating sludge incineration ash includes a phosphorus extraction process S1 for extracting phosphorus contained in sludge incineration ash, into an alkaline reaction liquid to obtain a phosphorus extract and alkali-treated ash; an acid treatment process S5 for mixing the alkali-treated ash with an acidic solution to obtain acid-treated ash; a phosphorus recovery process S12 for recovering phosphorus contained in the phosphorus extract, as phosphate; and a neutralization process S7 for mixing the acid-treated ash with at least one of alkaline waste liquid discharged between the end of the phosphorus extraction process and the end of the phosphorus recovery process, and alkaline waste liquid discharged between the end of phosphorus extraction process and the end of the acid treatment process, to raise the pH of the acid-treated ash. |
