Enhanced Degradation of a Model Oil Compound in Soil Using a Liquid Foam-Microbe Formulation

Abstract

This paper describes the development of a protein-based foam formulation and subsequent investigations into its suitability to enhance the degradation of a model hydrocarbon (n-hexadecane) using novel bench-scale soil microcosms. High-density protein-based foam concentrates based upon those developed by the fire-fighting industry were selected for experimental investigation. Using crude protein hydrolysate as a starting material, a foam formulation was developed with properties suitable for bioremediation studies. This formulation incorporated eight hydrocarbondegrading bacteria that had been selected for their ability to degrade hexadecane. In addition to their ability to utilize n-hexadecane, the bacteria were tested for compatibility with the foam formulation and each other. Seven individual Acinetobacter spp. and a Pseudomonas species were selected for use in the consortium based on these criteria. The use of this "bioactive foam" led to enhanced n-hexadecane degradation when compared to controls without foam. Following 7-d incubation, 60% of the n-hexadecane remained in the soil column using a foamed formulation, as compared to 90% with a nonfoamed control. In a subsequent experiment over a 15-d time course, the authors observed significantly greater n-hexadecane degradation in response to oxygenated bioactive foam treatment.

A bioactive foam reactor for the removal of volatile organic compounds: system performance and model development

“…In the liquid phase, the toluene concentrations also increased rapidly, but the values were much lower than the theoretical equilibrium concentration calculated using the Henry's law constant at the elevated toluene-loading rate, implying that active microorganisms could effectively biodegrade toluene, even under this transient-loading condition. However, the BFR system in this study appeared not to possess sufficient sorption capacity to dampen the inlet-loading changes, since the surfactant concentration was maintained at less than its critical micelle concentration and organic chemicals such as oleyl alcohol were not added to increase sorption capacity in the liquid phase [13,15]. As a result, the addition of chemicals capable of absorbing pollutants needs to be considered if the BFR system is frequently subjected to dynamic-loading conditions.…”

“…Instead of utilizing a fixed biofilm, several innovative approaches using suspended microorganisms have been proposed for the biological treatments of VOCs [11][12][13].…”

Drainage mechanism of microbubble dispersion and factors influencing its stability

“…This feature coupled with a large interfacial area arising from the small bubble size has resulted in its applications in separation processes [5][6][7][8][9]. It has been suggested that microbubble dispersions can enhance bioremediation by effectively increasing mass transfer of oxygen and nutrients in the subsurface [10][11][12].…”

Mechanisms for enhanced biodegradation of petroleum hydrocarbons by a microbe-colonized gas-liquid foam

“…These foams can be applied as a blanket over a contaminated site which, in turn, can enhance hydrocarbon removal (Stabnikova et al . 1996; Ripley et al . 2000).…”