Contaminant Removal from Recirculated White Water by Ultrafiltration and/or Biological Treatment, 1995 Environmental Conference Proceedings

P. Elefsiniotis

The University of Manitoba

E.R. Hall and R.M. Johnson

The University of British Columbia

The closure of white water systems in the paper-making industry has resulted in a number of problems such as increased concentrations of dissolved and colloidal white water contaminants, diminished product quality, and reduced paper machine runnability. This study investigated the potential of ultrafiltration technology and/or biological treatment to remove contaminants such as total dissolved solids (TDS), chemical oxygen demand (COD), total organic carbon (TOC), and resin and fatty acids (RFAs) from recirculated white water. Batch ultrafiltration experiments indicated that TDS, soluble COD, and TOC removal efficiencies were affected by membrane molecular weight cut-off, but were independent of the operating temperature, in the 20 to 60 °C range. Except for fatty acids, where average removals exceeded the 90% level, the separation efficiency of the process for all other parameters (TDS, soluble COD, TOC, and resin acids) was rather moderate, ranging from 10 to 41%. Biological treatment in a 10-L sequencing batch reactor (SBR) unit operated at 20 or 30 °C was found to be very effective for the removal of RFAs (> 90% removal); TOC, total and soluble COD (>70% removal). However, only 35% of the TDS content was reduced in the bioreactor. The variation in temperature did not have an effect on the process efficiency. Furthermore, ultrafiltration of the biologically treated process water resulted in significant additional TDS, soluble COD, and TOC removal.