Treatment of a foul condensate from kraft pulping with horseradish peroxidase and hydrogen peroxide

Foul condensates originating from the Kraft recovery process contain phenolic compounds whose removal might render these process streams more useful for reuse in other plant operations or more amenable to biological degradation. Treatment of a foul condensate with horseradish peroxidase and H2O2 selectively targeted phenolic compounds resulting in a reduction of the total phenols concentration below 1 mg/L as well as a substantial toxicity drop as measured using the Microtox® assay; however, only marginal COD removal was achieved. Comparisons of treatments between synthetic wastewaters and real wastewaters to which phenol were added revealed that the condensate contained species that protect the enzyme from inactivation by reaction products. Analytical data as well as experimental results suggest that these species are lignin derivatives.