| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a treatment method by which phosphorus is removed from organic polluted water containing phosphorus so as to recover the phosphorus as a resource, production of excess sludge can be decreased to substantially zero amount, and moreover, the use amount of an aluminum-based phosphorus removing agent can be decreased. SOLUTION: In the biological treatment of organic polluted water containing phosphorus, an aluminum-based phosphorus removing agent is added to make the phosphorus insoluble and to precipitate the insoluble phosphorus with activated sludge. Then an alkali agent is added to the precipitated sludge to elute phosphorus from the sludge as well as to make the activated sludge soluble. Then the solid content is separated from the liquid and the separated sludge is supplied to the above biological treatment process. Magnesium ion or calcium ion is added to the separated liquid to recover the eluted phosphorus as magnesium ammonium phosphate or calcium phosphate. Then the liquid from which the phosphorus is recovered is returned to the biological treatment process and reused for the removal of phosphorus.</p> |
