SEWAGE TREATMENT APPARATUS

摘要

PROBLEM TO BE SOLVED: To provide a sewage treatment apparatus capable of keeping stable phosphorus removing capacity. SOLUTION: In a sewage treatment apparatus constituted by providing an elution tank 8 for eluting iron ions or aluminum ions in a sewage treatment tank 1 and providing a supply means for supplying iron ions or aluminum ions eluted in the elution tank 8 to the treatment tank 1, the discharge port 9 for discharging the sludge accumulated in the elution tank 8 is provided to the lower part of the elution tank 8 and the closing means for closing the discharge port 9 in a freely openable and closable manner is provided.