Environmental Aspects of Biosulfite Pulping, 1995 Engineering Conference Proceedings

Gary M. Scott, Masood Akhtar, Marguerite Sykes, Said Abubakr

USDA Forest Service

In this study, we examined the effect of fungal pretreatment of wood chips prior to sodium- and calcium-based sulfite pulping. The pretreatment involved a 2-week incubation of loblolly pine chips with two strains (CZ-3 and L-14807 SS-3) of the white-rot fungus Ceriporiopsis subvermispora. Focus was on the kappa number and yield, effluent quality, and pulp bleachability after pulping. During sodium bisulfite pulping, the fungal pretreat-ment reduced the kappa number by 27%, with slightly lower pulp yield compared to the control. The two strains produced about the same results. However, during calcium-based sulfite pulping, strains CZ-3 and SS-3 reduced the kappa number by 48% and 21%, respectively, compared to the control, but had the same pulp yield as that of the control. Also, the CZ-3 pre-treatment during calcium-based pulping reduced the effluent toxicity substantially compared to the control; BOD and COD remained unaffected. During calcium-based sulfite pulping, the brightness of the control pulp increased from 54% to 80%, whereas the brightness of the pretreated pulp (CZ-3) increased from 49% to 80%, with a comparable 4% hydrogen peroxide charge. These results clearly demonstrate that this fungal pre-treatment is environmentally benign and offers much potential for sulfite pulping.