| 摘要 |
The invention provides a cleaning process for an immersion-type separating membrane device that allows convenient and reliable cleaning of contaminants that have adhered onto membrane surfaces of separating membrane devices, as well as a cleaning system for an immersion-type separating membrane device. Cleaning is carried out by injecting the chemical solution from the filtered water side of the separating membrane device 3 with the separating membrane device 3 set in a tank 2, thereby allowing matter that is to be removed, on the membrane surface of the separating membrane device 3, to be cleaned by a simple procedure without requiring large amounts chemicals. The chemical solution is injected with the values of X (kPa), as the pressure difference between membranes before the start of cleaning during filtration, and Y (kPa), as the initial pressure difference between membranes at the initial injection of the chemical solution during back pressure cleaning, satisfying the relationship -0.375X + 30 ‰¤ Y ‰¤ 0.5X + 80. The chemical solution can permeate to the outer surface in the film thickness direction even at sections where the precipitated matter to be removed has become hardened. It is also possible to obtain sufficient time for reaction between the matter to be removed and the chemical solution. This allows removal of the matter to be removed throughout the entire separating membrane device. |
