Multicomponent Adsorption Of Polycyclic Aromatic-Hydrocarbons In Manufactured-Gas Plant Soils

Adsorption is an important process in the bioremediation of Manufactured Gas Plant (MGP) soils contaminated with high levels of polycyclic aromatic hydrocarbons (PAH). Over 2,000 sites nationwide exist that are contaminated with complex mixtures of PAH and other pollutants. Many PAH are classified as EPA priority pollutants. The adsorption properties of weathered contaminated soils are difficult to measure using pulse or step perturbations due to heterogeneous contaminant distributions and heterogeneous soil physical structure. This study compares the use of cyclical perturbations with step change perturbations to analyze these complex soil systems. The sinusoidal method proved to be more robust than the step perturbation method. Sinusoidal response was easier to interpret and was continuous. The step change method produced a transient response that was more difficult to interpret. Two parameters, period and amplitude, were available when using sinusoidal perturbation methods while only one parameter, magnitude of the step function, was available for dynamic studies using traditional step perturbation methods. Displacement behavior was observed with both sinusoidal and step experiments. Simulations are presented using favorable isotherms for an adsorption system using a sinusoidal feed input. Automated on-line high performance liquid chromatography and capillary gas chromatography systems developed for analysis are also described.