Integrated cleaning of coloured waste water by ceramic NF membranes

New TiO2-NF membranes with a mean pore size of 0.9 nm and a cut-off of 450 D were tested in decolouring of textile waste water. A pilot plant with a m embrane area of 5.1 m(2) was integrated in the textile finishing in order t o treat only the coloured parts of the waste water near the colouring and w ashing machines and to recycle the hot permeate as process water. The pilot plant was tested with 30 types of different coloured waste water over a pe riod of 6 weeks to detect optimal parameters for the filtration process wit h a focus on high flux and low running costs. Due to the differences in the composition of the dyes a decolouring of 70-100% was obtained. The fluxes varied between 0.2 and 1.1 m(3)/h, whereas the running costs were 0.50-2.80 DM/m(3) permeate, respectively. (C) 2001 Elsevier Science B.V. All rights reserved.