Determination of Microbial Sorption Isotherms from Column Experiments

Abstract

Microbial sorption isotherms cannot be obtained using the traditional batch methods owing to the difficulty of distinguishing between reversible and irreversible sorption. In this research, we investigated microbial sorption isotherms of Pseudomonas fluorescens, Pseudomonas putida, and Pseudomonas sp. on an alluvial loam from the Central Oklahoma Aquifer (COA) using column experiments. All these three bacterial strains displayed a concave isotherm on COA, which can be described by the Freundlich sorption isotherms. We explained the concave‐shaped microbial sorption isotherms using the surface thermodynamic theory. In this study, we also investigated the impact of transport velocity on the microbial breakthrough curves. We found that the same bacterial strain had the same sorption isotherms but different deposition coefficient at different flow rates. The high solid to solution ratio of column experiments is close to that which is encountered in the natural systems, which makes this method a useful tool for guidance of in‐situ bioremediation.