Animal waste is a valuable resource, which, when managed properly, can reduce the need for commercial fertilizer. Similarly, as a new recognized water resource, nutrient-rich reclaimed wastewater supplies not only water, but also plant nutrients (especially nitrogen and phosphorus) that can benefit agricultural production. When animal waste or reclaimed wastewater is used for land applications or agricultural irrigation, the major concern is the possible spreading of infectious agents or pathogenic organisms in the soil and the subsequent possibility of groundwater contamination once the infectious agents or pathogenic organisms pass through the vadose zone and reach the groundwater table.

Objectives:

Our major research interest concerns the impact of physiological growth stage and macro nutrient ratio on the fate and transport of S. Typhimurium and E. coli O157:H7 in the subsurface soil. We believe that the transport of S. Typhimurium and E. coli O157:H7 is controlled by their interactions with the surrounding environment, which are determined by their surface thermodynamic properties. This project seeks to provide operation strategies for animal waste land applications and reclaimed wastewater agricultural irrigation. Three major thrusts will be focused on this project: (1) S. Typhimurium and E. coli O157:H7 surface property characterization and interaction quantification under different physiological stage and macro nutrient ratio conditions, (2) S. Typhimurium and E. coli O157:H7 transport conceptual model development and validation, and (3) implementation of research discovery in field applications.

Publications:

^* indicates corresponding author and underline indicates graduate students working on this project.

1. Chen, G., A. Driks, K. Tawfiq, M. Mallozzi and S. Patil, 2010, Bacillus anthracis and Bacillus subtilis spore surface properties and transport, Colloid Surface B., 76, 512-518.

2. Chen, G.^*, 2008, Bacterial interactions and transport in unsaturated porous media, Colloid Surface B., 67: 265-271.

3. Penagonda Srinivasa Ranga, V., A. Chan Hilton and G. Chen^*, 2008, Lipopolysaccharide extraction on bacterial adhesion and transport, J. Adhes. Sci. Technol., 22: 1073-1088.

4. Chen, G.^*, P. Subramanian and K. Tawfiq, 2010, Bacterial deposition in unsaturated porous media as related to surface properties, Int. J. Environ. Pollut., 40: 363-379.

5. Chen, G.^*, V. Penagonda Srinivasa Ranga, Y. Mao, K. Chen and H. Qiao, 2008, Impact of lux gene insertion on bacterial surface properties and transport, Res. Microbiol., 159: 145-151.

This project is related to agricultural applications. When animal waste is introduced to agricultural soil, pathogen transport might coincide with in situ colloid mobilization. The following papers were generated based the colloid mobility observations.

1. Chen, G.^*, J. Liu, K. Tawfiq, K. Yang and C. Banks, 2009, Colloid retention in unsaturated porous media as impacted by colloid size, Part. Sci. Technol., 27: 35-49.

2. Patil S., J. Zhang, K. Tawfiq and G. Chen^*, 2009, Colloid interactions and transport in porous media as impacted by water chemistry, J. Adhes. Sci. Technol., 23, 1845-1859.

Published Abstracts and Presentations:

1. Chen, G., Bacterial interactions and transport in unsaturated porous media, 2009 USDA-CSREES National Water Conference, St. Louis, Missouri, February 9-12, 2009.

2. Subramaniam, P. K. and Chen, G., Bacterial transport in unsaturated porous media, Joint Annual Meeting, Southeastern Branch and Florida Branch ASM, Jacksonville, November 6 - 8, 2008.

3. Patil, S., Driks, A., Mallozzi, M. and Chen, G. Bacillus anthracis and Bacillus subtilis spore surface properties and transport, Joint Annual Meeting, Southeastern Branch and Florida Branch ASM, Jacksonville, November 6 - 8, 2008.

4. Chen, G., Impact of lux gene insertion on bacterial surface properties and transport, 2008 USDA-CSREES National Water Conference, Sparks, Nevada, February 3-7, 2008.

5. Penagonda Srinivasa Ranga, V. and Chen, G., Impact of lipopolysaccharide extraction on bacterial transport, 60^th Annual Meeting of Southeastern Branch of American Society of Microbiology, Auburn, November, 2007.

6. Patil, S. and Chen, G. Bacterial transport as impacted by solution ionic strength, 60^th Annual Meeting of Southeastern Branch of American Society of Microbiology, Auburn, November, 2007.

Intact Column from Agricultural Sites and Laboratory Experiment Assembly

Matric Potential, in situ Colloid Release and S. Typhimurium and E. coli O157:H7 Breakthrough Curves

Experimental Agricultural Site

Layout of the Lysimeters at the Experimental Agricultural Site

Laboratory Experiments and Data

Field Site and Lysimeter Layout

Students Presenting Research Results at Conferences

Pawan, Joint Annual Meeting, Southeastern Branch and Florida Branch ASM, Jacksonville, November 6 - 8, 2008

Sandip, Joint Annual Meeting, Southeastern Branch and Florida Branch ASM, Jacksonville, November 6 - 8, 2008

Acknowledgement

The work was supported by the National Research Initiative of the USDA Cooperative State Research, Education and Extension Service, Grant No. 2007-35102-18111 to Florida A&M University.

PFAS Chain Length

Hinkley Funded Projects Summary 2

Hinkley Funded Project Summary 3