Nanofiltration of dye (crystal violet) is carried out in a rectangular cross-flow cell. The feed concentration of the dye is selected in the range generally encountered in the actual textile plant effluent. Apart from the feed concentration, the effects of other operating conditions, e.g. transmembrane pressure and cross-flow velocity are studied as well. The effects of these operating conditions on the permeate flux and observed retention are evaluated by conducting one complete set of experiments (consisting of 27 experiments) under a laminar flow regime. Thin wires are used as turbulent promoters and the full set of experiments is carried out under the same operating conditions (as in the laminar flow). It is observed that the significant flux enhancement in the range of 40-100% is achieved while the retention of dye remains unchanged. (C) 2004 Elsevier B.V. All rights reserved.