Combined Alkali Precipitation and Bioaugmentation Process for the Treatment of Black Liquor under Alkaline Condition

This study focuses on evaluating the efficiency of an integrated treatment of original black liquor (BL) using combined alkali precipitation and bioaugmentation process. The results of alkali precipitation showed about 71.6% chemical oxygen demand (COD), 83.2% lignin and color 94.5% were successfully removed. Combined treatment showed an increased reduction of COD, lignin and color in relation to the non-combined treatments. A lab scale (5l) study was carried out for fresh original black liquor without pH adjustment. The results of the study revealed a high synergic effect of the combined treatments, reducing the color of black liquor by 92.3∼94.6%, lignin was reduced by 90.6∼91.8%, cellulose and hemicellulose were reduced by 53.2∼61.7% and 42.5∼48.3%, respectively, the reduction of Biochemical Oxygen Demand (BOD) and COD was 88.7∼91.2% and 87.2∼89.0%, respectively.