| 摘要 |
<p> Desalinated water is stably produced with minimal membrane degradation and fouling during operation of a water treatment apparatus based on a reverse osmosis membrane using natural energy as primary power. A method for pressurizing water to be treated, feeding the water to a semipermeable membrane unit (7), treating the water, and obtaining desalinated water by using as the primary power source electric power obtained from a natural energy generator unit (15), wherein a minimum feed water pressure (Pfmin) is determined on the basis of an osmotic pressure calculated from the quality of the water to be treated that is fed to the semipermeable membrane unit (7), and if the pressure cannot be raised to Pfmin when a preset minimum water flow volume (Qfmin) of feed water has been supplied, either an operation is carried out in which the recovery ratio (R), which is the value of the ratio of the passed water flow volume (Qp) to the fed water flow volume (Qf), is set to zero, or the operation of the semipermeable membrane unit (7) is stopped and the recovery ratio (R) is controlled so that the concentrated water flow volume does not exceed Qfmin when the pressure can be raised to Pfmin.</p> |
