Study on Recycling Alkali from the Wastewater of Textile Mercerization Process by Nanofiltration

This study has researched the treatment ability of nanofiltration technology in printing and dyeing mercerization process alkali wastewater and investigated the effect of different pressures and alkalinities on membrane flux. The effect of different operating conditions on COD removal rate and alkali penetration rate has been also investigated in this study. The experimental results show that nanofiltration technology can remove the COD in printing and dyeing mercerization process wastewater effectively and the removal rate is above 80%. We conclude that the membrane flux tends to increase as the operating pressure increases, and decrease as the concentration of alkali in feed liquor and COD increases. The infiltration liquor through membrane can be satisfactorily reused by the method of concentration, and the final recovery efficiency of alkali by nanofiltration membrane treatment is above 90%.