Determination of nanofiltration membranes for reuse of paper mill industry wastewater

Abstract

In this study operating pressure driven systems which is known their efficiency in literature, for paper and pulp industry wastewaters in batch conditions were executed by using NFloose/NFtight membrane combination. The batch NFloose/NFtight experiments were respectively applied at 12 and 20 bars by conventional membrane filtration process, at a stirring rate of 300 cycle/min, at pH 10 and at a temperature of 25 degrees C. Determination of most suitable membrane at batch operating conditions were made by using 8 different membranes (for NFloose NP010, NFG, MPF36 and CK3001 and for NFtight NP030, NF270, DS-5DK, ESNA) through organic matter removal and filtrate flux values. In NFloose membranes at a filtrate flux of 4.12 L/m(2) h removal of 61.0% TOC and 76.9% COD and MPF36 membrane was determined to be best NFloose membrane. The filtrate water obtained by MPF36 were later passed through NFtight membranes. In all NFtight membranes generally the organic matter removal efficiency was good and ESNA was selected to be the best membrane in terms of effluent quality by obtaining organic matter removal at rates of 93.9% TOC and 94.2% COD with 10.05 L/m(2) h filtrate flux. From this point of view, in short term operation of paper wastewaters by pressure driven NFloose/NFtight integrated membrane system, it was seen that good quality of outlet water with 7.15 pH and a conductivity coefficient of 144 mu S/cm and at 13 mg/L TOC and 28 mg/L COD concentrations could be obtained also that good quality of reuse water could be produced in terms of aimed effluent water.