Kinetics of microbial growth and biodegradation of methanol and toluene in biofilters and an analysis of the energetic indicators

Abstract

The kinetics of microbial growth and the biodegradation of methanol and toluene in (a) biofilters (BFs), and (b) biotrickling filters (BTFs), packed with inert materials, has been studied and analyzed. The specific growth rate, μ, for the treatment of methanol was 0.037 h −1 for a wide range of operating conditions. In the BF, μ was found to be a function of the methanol and toluene concentrations in the biofilm. In the BF used for treating methanol, μ was found to be affected by (1) the nitrogen concentration present in the nutrient solution, and (2) the kind of packing material employed. The kinetics of the methanol and toluene biodegradations were also analyzed using “mixed order” models. A Michaelis–Menten model type provided a good fit for the elimination capacity (EC) of the BTF treating methanol, while a Haldane model type provided a good fit to the EC of the BF treating methanol and toluene. The carbon dioxide production rate was related to the packed bed temperature and the content of the volatile solids within the biofilm. For the BF, the ratio of temperature/carbon dioxide production rate (PCO 2) was 0.024 °C per unit of PCO 2, and for the BTF it was 0.15 °C per unit of PCO 2.