Growth Kinetics of Acclimated Mixed Culture for Degradation of Isopropyl Alcohol (IPA)

Abstract

Iso-propyl alcohol (IPA) is an organic chemical regarded as a potential pollutant. The permissible exposure limit (PEL) of IPA specified by Occupational Safety and Health Administration (OSHA) is 400 mg L-1. In this study the aerobic biodegradation of IPA is carried out by an acclimated mixed culture obtained by sewage treatment plant, for the range of 200-700 mg L-1 of initial IPA concentration. The batch degradation study demonstrated that the maximum growth rate obtainable is 0.337 h-1. To explain the inhibition effects, different kinetic growth models such as Haldane, Luong and Edward models are applied. The experimental data are found to fit well with inhibition models having the values of coefficient of determination (R2) of 0.989, 0.986 and 0.984 respectively for Haldane, Luong and Edward models. Based on the disappearance of IPA, degradation is modeled by the three-half-order kinetics and the resulting kinetic parameters are reported.