| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a waste water treatment apparatus in which, when facilities of an activated sludge process are updated or reconstructed, the surface of a membrane can be cleaned stably and water treatment using activated sludge can be stabilized even in the case that a membrane separation unit is installed in a precipitation tank, and to provide an update/modification method of the waste water treatment apparatus.SOLUTION: The waste water treatment apparatus is characterized in that organic sewage and activated sludge are aerated and mixed with each other in an aeration tank, an obtained liquid mixture is subjected to solid-liquid separation in the precipitation tank, the concentrated sludge obtained by the solid-liquid separation is returned to the aeration tank as return sludge, and the membrane separation unit, in the lower part of which an aeration device for cleaning the surface of the membrane is arranged, is installed in the precipitation tank so that flow rate of the return sludge is made higher than that of the return sludge of the existing activated sludge process. The update/modification method of the waste water treatment apparatus is also provided.</p> |
