Influence of Influent Concentration on Papermaking Black Liquor Treatment with Wet Air Oxidation Method

Abstract

Black liquor was processed with wet air oxidation technology in these experiments. Influence of its influent concentration was researched. COD, absorbance, turbidity and pH of the water samples were measured and analyzed. The results showed that: the treatment effect of each index in black liquor treatment with wet air oxidation method gradually weakened with the increase of influent concentration from the overall point of view; when papermaking black liquor was processed by wet oxidation, the water samples was weak alkaline basically, with pH in between 7.83 to 8.70. COD removal, decolorization removal and turbidity removal basically improved with the extension of time, the COD removal and decolorization removal can reach 50 % or more basically. When influent concentration was greater than 5500 mg/L, turbidity removal was less than 40 %. So the influent concentration of the black liquor in wet oxidation treatment should not be too large, the influent concentration of 2500 mg/L to 4000 mg/L is appropriate.