KRAFT WASTEWATER TREATMENT IN AERATED LAGOON USING LIGNOCELLULOLYTIC ENZYMES

The objective was to evaluate the Kraft effluent treatment process in facultative lagoons in the presence of ligninolytic enzymes (laccase). Furthermore, an experimental design to determine the effects of pH, temperature and amount of commercial ligninolytic enzyme was used. Moreover, the performance of the same enzyme under environmental conditions of facultative lagoons at bench scale was studied for 60 days. According to the results obtained in a factorial design it can be concluded that the use of laccase enzyme, under conditions optimized by experimental design, showed a positive influence on lignin removal, color and spectral area, the most efficient conditions being 50ppm, pH 4 and temperature 37 degrees C. The effect of the use of laccase in the removal of phenolic compounds was not considered significant by an ANOVA test, thus increasing the complexity of enzymatic processes, involving conditions of pH, temperature and substrate. The results of the continuous flow experiment show that the facultative aerated lagoon assisted with laccase enzymes removed 86, 52, 20 and 30% of BOD, COD, color and lignocellulosic compounds, respectively, even though these values were not statistically different from those obtained in the absence of enzymes.