Integral Approach for Improving the Degradation of Recalcitrant Petrohydrocarbons in a Fixed-Film Reactor

Abstract

The degradation of diesel and phenanthrene in waste water was studied in a column combining a submerged trickling-flow with a fixedfilm at a determined biofilm thickness with recirculation. Degradation efficiencies were found to be high with the production of a biofilm thickness of 789 μm structured in a package material with proper adsorption and physicochemical properties necessary to reach a stable state condition for the degradation of recalcitrant components in 78% at a retention time of 3 h. Improved degradation rates were reached with a biofilm built from an adapted inoculum that showed the presence of Pseudomonas sp., Klebsiella sp. Enterobacter in a concentration of 6.45×10 9 CFU mL −1 . Moreover, the biodegradation rate of the inoculumn was quantified. The diesel kinetic experimental data were well described by Gompertz model which provides a specific grow rate (Kb) of 0.76±0.36 h −1 and a correlation of R 2 =0.93. The integral approach study of the variables of a complex degradation process lead to improve the complete operation of the reactor in comparison with other more specific component-based approaches.

The marine bacteriumMarinobacter hydrocarbonoclasticusSP17 degrades a wide range of lipids and hydrocarbons through the formation of oleolytic biofilms with distinct gene expression profiles

“…No biofilm was observed on nonmetabolizable HOCs such as branched alkanes (Klein et al, 2008). In a few studies, they have been shown to increase the rate of mass transfer of hydrocarbons by reducing the diffusion path of the substrate (Golyshin et al, 2002;Johnsen et al, 2005;Grimaud, 2010;Harms et al, 2010b;Jim enez et al, 2011;Jung et al, 2011;Notomista et al, 2011;Tribelli et al, 2012). Furthermore, the rate of n-hexadecane degradation decreased dramatically when the biofilm was disorganized, thus confirming that biofilm formation may constitute an efficient adaptive strategy for assimilating alkanes (Klein et al, 2008).…”

“…Such biofilms, which have been observed with many strains or consortia degrading aliphatic or aromatic hydrocarbons, are thought to provide bacteria with efficient mechanisms to access hydrocarbons. In a few studies, they have been shown to increase the rate of mass transfer of hydrocarbons by reducing the diffusion path of the substrate (Golyshin et al, 2002;Johnsen et al, 2005;Grimaud, 2010;Harms et al, 2010b;Jim enez et al, 2011;Jung et al, 2011;Notomista et al, 2011;Tribelli et al, 2012). A proteomic study was conducted on M. hydrocarbonoclasticus SP17 biofilm growing on n-hexadecane (Vaysse et al, 2009).…”