| 摘要 |
PURPOSE:To perform the pretreatment of the liquid to be treated smoothly and maintain the effect of permeable membrane treatment at a high level by making use of the pressure of the membrane side residual liquid discharged from a membrane separating process for backwashing of fielter media in desalting treatment, etc. CONSTITUTION:The water to be treated enters a precision filter device C-1 through a sand filter device A, whereby it is further filtered. This filtrate is boosted by a boosting pump P-2, and is fed and pressured to a permeable membrane device D, by which it is separated to membrane permeated liquid I and membrane side residual liquid II. This liquid II is clear liquid of high pressure and is reduced of pressure by a pressure regulating valve (j), thence it is discharged to the outside of the system. When the device C-1 clogs, it is changed over to a stand-by precision filter device C-2, and after the liquid II of high pressure is reduced of pressure, it is passed through piplines 15, 6 and is discharged to the outside of the system after backwashing the media in the device C-1. By this method, the need for the clear filter water for backwashing is eliminated and the running costs are saved. |
