Anaerobic biodegradation of phenol: inhibition kinetics and system stability

The Haldane inhibition model was used to describe the anaerobic microbial biodegradation of phenol. Experimental data on the biodegradation of phenol obtained from a continuous flow anaerobic fermenter and a series of closed batch reactors were analyzed. Phenol was found to have a very low half velocity coefficient, Ks, value of 0.03 mg/L. Other kinetic parameters included a maximum specific utilization rate, k, of 0.027hr-1, a haldane inhibition constant, Ki, of 363 mg/L, a biomass yield factor, Y, of 0.16 mg VSS/mg phenol, and a biomass decay coefficient, b, of 0.0008hr-1. Analytical system stability studies on the continuous flow fermenter operating at steady state were theoretically simulated using the phenol kinetic parameters. Pulse and step increases in phenol influent feed concentration were simulated and the response of the fermenter was analyzed using a computer program. Conditional and unconditional recovery regions from a pulse feed input were identified. For each influent phenol concentration...