Bacterial Sorption to Soil Particles: Advancing Understanding of Safer Water Supplies and Bioremediation
AIChE Annual Meeting
2007
2007 Annual Meeting
Education
Student Poster Session: Environmental
Monday, November 5, 2007 - 8:30am to 11:00am
Bioremediation is a natural process to fight pollution where microorganisms chemically transform contaminants by degradation. Understanding bacterial transport is critical to predicting bioremediation because the microorganism must be close to the contaminants. During bacterial transport towards a contaminant, sorption of bacteria to soil is not desirable; however, it is desirable once the bacteria reach the contaminant. Some microorganisms are capable of swimming preferentially towards a nutrient gradient through a process called chemotaxis. The objective of this investigation was to determine the sorption coefficient of two strains of Escherichia coli (GFP and HCB1) and test the potential effects of chemotaxis on sorption. The tests were conducted using 10g sand columns placed in 20mL syringes comparing grains of 0.5 and 0.1mm diameter. Bacteria were injected into the columns and equilibrated for six hours; then the columns were flushed with deionized water and the effluent was transferred onto microscope slides for enumeration of the bacteria. The results showed a linear relationship between the number of bacteria injected and the number of bacteria adsorbed, even at high concentrations (109 cells/ml). The sorption coefficients increased with decreasing particle size due to the increase in specific surface area. The impact of chemotaxis on adsorption was not established due to poor trapping of the attractant in artificial grains. The sorption coefficients will be used in mathematical models to predict the migration of injected bacteria in a larger-scale field investigation.