A combined fungal and enzyme treatment system to remove TMP/newsprint mill white waters substances.

Application: This study shows that a combined and enzyme treatment can mitigate problems associated with the build-up of detrimental organics during system closure.

This study assessed a combined fungal and enzyme system for use as an internal water treatment "kidney" in a TMP/newsprint mill with a closed water system. We determined the ability of" this fungal and enzyme treatment to remove various dissolved and colloidal substances (DCS) present in different white water samples. The three different white water samples we used included a typical mill white water (MWW) obtained from a TMP/newsprint mill, a "model" recycled white water (RWW), and a membrane-filtered "model" recycled white water (FWW) prepared in the PAPRICAN pilot plant.

The growth of the white-rot fungus Trametes versi-color on those waters resulted in a significant decrease in the amount of total dissolved and colloidal substances. Fungal treatment removed more than 75% of the extractives and 62% to 71% of the carbohydrates originally present in the three white waters by the end of 7 days. The fungal enzyme treatments degraded considerable amounts of the detrimental DCS components.

A 3-hour FCF treatment at 65 [degrees] C removed more than 90% of the lignans and ester bonded extractives (stery1 esters and triglycerides) from both of the white waters. In addition, the resin and fatty acids content decreased by approximately 40% and 60% in the respective mill white water and model white water samples. The fungal and enzyme treatments also resulted in the polymerization of low molecular weight phenolics into higher molecular weight lignin-types of material. These results showed that a combined fungal and enzyme treatment could provide a means of mitigating the problems associated with the build-up of detrimental organics during mill water system closure.

Zhang, Stebbing, Soong, and Saddler are with the Faculty of Forestry at The University of British Columbia in Vancouver, Canada; Beatson is with Advanced Papermaking Initiative, British Columbia Institute of Technology in Burnaby, Canada. Contact Saddler by e-mail at [e-mail].