Reducing Water Pollution from Pulp Mill Sulfite Wastes.

摘要

To abate the pollution by pulp mills'discharge of spent sulfite liquor into streams and lakes a process utilizing sulfur reducing anaerobic bacteria of the genus Desulfovibrio was conceived. Cultures of these organisms obtained by soil enrichment were adapted to utilize the lignosulfonate present in spent sulfite liquor as both a source of carbon and of sulfur. Sulfur was metabolized to H2S and can be recycled in the pulping process. Any organic fragments of the molecule not converted to CO2appear to lose insolubility and can be removed as sludge disposal or conversion into useful organic products. Some lignosulfonate molecules were readily metabolized;however,the rate of digestion slowed preceptibly with time. The decrease in rate appears to be due to the varying resistance of different sulfur bonds to enzymatic breakdown. The loosely bound sulfur is easily removed during the first 5days fermentation. Digestion of the tightly bound sulfur decreases drastically and complete removal does not appear feasible. During the initial 5day fermentations sulfur reductions of 20% coupled with the COD reduction of 30% were consistently obtained.