Model description and kinetic parameter analysis of MTBE biodegradation in a packed bed reactor.

A dynamic modeling approach was used to estimate in-situ model parameters, which describe the degradation of methyl tert-butyl ether (MTBE) in a laboratory packed bed reactor. The measured dynamic response of MTBE pulses injected at the reactor's inlet was analyzed by least squares and parameter response surface methodologies. Response surfaces were found to be statistically significant and thus suitable for estimating the global minimum as well as the 95% parameter uncertainty regions. The linear parameter uncertainty estimates for the half-saturation constant (K(S)) and the maximum growth rate (micro(max)) were: 0<K(S)<10 mg COD/L and 0.12<micro(max)<0.25 d(-1). Obtaining reliable parameters is a necessary step towards model application in order to study practical reactor operational problems such as the competition between the relatively slow growing MTBE degraders and the oxidizers of other groundwater co-contaminants such as ammonium, benzene, toluene, ethylbenzene and xylenes.