Kinetics of toluene degradation in a biofilm system under denitrifying conditions

In this paper a variability study of the kinetics of toluene biodegradation in biofilm systems under nitrate reducing conditions is presented. A total of 10 kinetic experiments were performed: 4 with toluene as a single compound and 6 with toluene in the presence of a mixture of aromatic compounds (benzene, ethylbenzene and xylenes: BEX). When toluene was the only substrate the maximum utilization rate, k_x, and the half saturation constant, K_s, ranged between 1.3 to 1.8 d⁻¹, and 0.17 and 1.7 mg/L respectively. Based on the nitrite production, the average yield coefficient was 1.0 to 1.2 mg biomass/mg toluene degraded. Furthermore, it was shown that the presence of benzene, xylenes and ethylbenzene significantly decreased the toluene removal.