Theses and Dissertations

Issuing Body

Mississippi State University


Truax, Dennis D.

Committee Member

Diaz-Ramirez, Jairo N.

Committee Member

Magbanua, Benjamin S.

Date of Degree


Document Type

Graduate Thesis - Open Access


Civil and Environmental Engineering

Degree Name

Master of Science


James Worth Bagley College of Engineering


Department of Civil and Environmental Engineering


The effects of heavy metals, endocrine disruptors, and other contaminants on activated sludge and wastewater treatment operations have been studied extensively. However, the potential for infiltration of bacterial species not native to activated sludge has not been extensively examined. This project investigated the effect of the contamination of activated sludge wastewater treatment systems by Bacillus anthracis. From a pure culture of Bacillus megaterium inoculations of two bench-scale, sequencing batch reactors with different solids retention times was studied. Microbial enumeration testing was initially done on the mixed liquor alone, but to further detail the Bacillus path through the reactor, further testing was done to examine the supernatant. The data indicated that little effect would be caused from Bacillus inoculation of activated sludge reactors as population diversity returned to normal within a period of time equal to approximately one quarter of the solids retention time.



biological contamination