PURPOSE: To increase the separation and removing efficiency of an aromatic compound, which is conventionally difficult to remove only by active carbon adsorption method, by evaporating and condensing an aromatic compound containing waste water under a reduced pressure and supplying to a separating device provided with an osmotic vaporization membrane to separate and recover the aromatic compound.

CONSTITUTION: In the case of treating the waste water containing the aromatic compound such as benzene, toluene, xylene, at first just as reduced pressure flash processing, the waste water is evaporated and condensed in the state of the reduced pressure to remain and separate a high b.p. material or a solid matter. The waste water after processed under the reduced pressure is supplied to the separating device 3 through a pipe line 1 and since one side A of the osmotic vaporization membrane 2 is evacuated by a vacuum pump 4, the major part of the aromatic compound permeates to the A side of the osmotic vaporization membrane 2, after condensed by a condenser 5, is introduced into a decanter 6, where the aromatic compound is separated from water due to the difference of specific gravity and is recovered from a circulating path 7. The waste water in the B side of the separating device is supplied to an activated carbon adsorption tower and after the residual aromatic compound is adsorbed on the activated carbon, is discharged.