A SIMPLIFIED METHOD FOR DETERMINATION OF KINETIC-PARAMETERS TO DESCRIBE THE AEROBIC BIODEGRADATION OF 2 IMPORTANT PHENOLIC CONSTITUENTS OF OLIVE MILL WASTE-WATER BY A HETEROGENEOUS MICROBIAL CULTURE

Determination of biokinetic parameters for tyrosol (4-hydroxyphenethyl alcohol) and caffeic acid (3,4 dihydroxy cynammic acid) (the two most representative phenolic compounds present in Olive Mill Wastewater, OMW) was achieved using a simplified Monod kinetic model. The experimental procedure utilized acclimated microbial cultures to which substrate was added at low concentration relative to the microbial mass. Nonlinear regression analysis confirmed the application of this approach by being able to accurately predict substrate utilization rates. Values for the maximum specific growth rate, mu(max), and the half-saturation coefficient, K-s, for tyrosol ranged from 0.4 to 3.5 days(-1) and from 6.2 to 18.5 mg/l respectively. The corresponding values for caffeic acid were 0.9 to 2.3 days(-1) and 9.5 to 39.7 mg/l. The biomass yield coefficients for tyrosol and caffeic acid were 0.55 and 0.62 mg VSS/mS substrate and the corresponding decay rates were 0.15 and 0.12 days(-1). The simplified approach yielded results that were comparable to values reported for other phenolic compounds determined using more sophisticated experimental and mathematical techniques.