| 摘要 |
PROBLEM TO BE SOLVED: To provide a membrane separation apparatus in which a part of concentrated water can stably be returned to the upstream side of a pressure pump.SOLUTION: The membrane separation apparatus comprises: a membrane module 7; a pressure pump 5 for discharging supply water W1 toward the membrane module 7; a return line L51 for returning a part W31 of concentration water W3 to the upstream side of the pressure pump 5; a water discharge line L61 for discharging a remainder W32 of the concentration water W3 to the outside; a circulation pump 21 which is arranged on the return line L51 and used for discharging the part W31 of the concentration water W3 toward the upstream side of the pressure pump 5; pressure detecting means PSW for detecting the pressure of the supply water W1 to be circulated on the upstream side of the pressure pump 5 on a supply water line L1 as a detected pressure value; and a control part 30 which controls so that the pressure pump 5 is stopped and the circulation pump 21 is driven when the detected pressure value exceeds a predetermined pressure threshold or the pressure pump 5 is driven and the circulation pump 21 is stopped when the detected pressure value falls below the predetermined pressure threshold. |
