MEMBRANE SEPARATION ACTIVATED SLUDGE TREATMENT APPARATUS AND METHOD OF OPERATING THE SAME

PROBLEM TO BE SOLVED: To provide a membrane separation activated sludge treatment apparatus that can improve the quality of treated water and suppress operation power, and to provide a method of operating the apparatus.SOLUTION: A membrane separation activated sludge treatment apparatus 1 comprises: a first biological reaction tank 20 that has aeration means (22, 24) and in which water to be treated is treated with activated sludge; a second biological reaction tank 30 in which the water to be treated is treated under an oxygen-free condition; a membrane separation tank 40 that has a membrane separator 41 and aeration means (42, 44) and in which the treated water is treated under an aerobic condition; a first treated water passage 110, 140 that makes the treated water of the first biological reaction tank 20 flow into the membrane separation tank 40; a connecting passage 120 that connects the second biological reaction tank 30 and the first biological reaction tank 20 to each other; a second treated water passage 130, 140 that makes the treated water of the second biological reaction tank 30 flow into the membrane separation tank 40; and a return passage that returns the treated water of the membrane separation tank 40 to the second biological reaction tank 30. 【課題】処理水質の向上と運転動力の抑制とを図ることを可能とした膜分離活性汚泥処理装置及びその運転方法の提供。【解決手段】散気手段（２２，２４）を有し、活性汚泥で被処理水を処理する第１生物反応槽２０と、無酸素条件下で被処理水を処理する第２生物反応槽３０と、膜分離器４１及び散気手段（４２，４４）を有し、好気条件下で処理水を処理する膜分離槽４０と、第１生物反応槽２０の処理水を膜分離槽４０に流入させる第１処理水流路１１０，１４０と、第２生物反応槽３０と第１生物反応槽２０とを接続する連結流路１２０と、第２生物反応槽３０の処理水を膜分離槽４０に流入させる第２処理水流路１３０，１４０と、膜分離槽４０の処理水を第２生物反応槽３０に返流させる返流流路とを備える膜分離活性汚泥処理装置１。【選択図】図１