Inhibition kinetics of phenolic compounds in aerobic degradation of organic wastewaters.

This study proposed a kinetic model for the aerobic degradation of high strength organic wastewaters with high concentrations of phenolic compounds. The model was based on the conventional Monod kinetic equation incorporating phenols' inhibition. Furthermore, a methodology for determining biokinetic constants was proposed. Olive-mill wastewater (OMWW) was used for the case study. The model and proposed methodology were fitted on the experimental data and it was proved that the aerobic degradation of OMWW was described satisfactorily. The following kinetic constants were determined: maximum specific substrate removal rate, 1.35 h(-1); minimum microorganisms decay rate, 0.01 h(-1); inhibition coefficient of phenolic compounds, 373 mg L(-1); half-saturation concentration in carbon units, 1004 mg L(-1); and decay acceleration coefficient of phenolic compounds, 231 mg L(-1). Finally, the biomass yield coefficient was found to be equal to 0.36. Thus, it was determined that the proposed methodology would be a useful tool for determining biokinetic constants of similar substrates.