| 摘要 |
PROBLEM TO BE SOLVED: To provide a high efficiency diafiltration method in which permeated flux is high and foulings onto the surface of a membrane are effectively prevented. SOLUTION: The liquid to be treated is supplied to one side of a membrane module 3a, in which permeation membranes are disposed, of a first membrane separation unit 21 and separated into the permeated liquid to be withdrawn from the other side and the impermeable liquid to be withdrawn from one side by vibrating the permeation membranes. A part or the whole of the impermeable liquid is returned to a supply tank 1a and the liquid in the tank 1a is forcibly sent to the module 3a while adding a cleaning liquid to the tank 1a to carry out the same permeation treatment as described above. The permeated liquid to be withdrawn from the other side is forcibly sent to one side of another membrane module 3b, in which permeation membranes are disposed of, of a second membrane separation unit 22 and separated into the permeated liquid to be withdrawn from the other side and the impermeable liquid to be withdrawn from one side while performing the same permeation treatment by vibrating the permeation membranes. A part or the whole of the impermeable liquid is returned to another supply tank 1b and the liquid in the tank 1b is forcibly sent to the module 3b to carry out the same permeation treatment as described above.
|
