Degree Type

Creative Component

Semester of Graduation

Fall 2019


Civil, Construction, and Environmental Engineering

First Major Professor

Timothy Gage Ellis


Master of Science (MS)


Civil Engineering


Aerobic granular sludge (AGS), a dense aggregated microbial community, is a new but promising biological wastewater technology. Due to its reduced footprint, better settlability, low biomass retention time, tolerance to toxicity, and nutrient reduction ability, AGS is far superior to the widely used Activated Sludge (AS). AGS is cultivated using up shear velocity and a feast-famine feed regime to form three microenvironments and enhance the abundance of EPS forming microorganisms and slow growing microbes like phosphate accumulating organisms (PAOs). AGS’s ability to reduce nutrients makes it a compelling option for point sources regarding the up and coming regulation changes from the Iowa Nutrient Reduction Strategy. Using BioWin, a biological modeling simulation software, AGS’s nutrient reduction ability was evaluated using the City of Ames Water and Pollution Control Facility’s (WPCF’s) raw water data to determine if it would be a feasible option for future implementation. Totally the four seasonal simulation the total nitrogen removal was shown to increase from an average of 33% to 73%. Similarly, the total phosphorus removal would increase from 19% to 87% making AGS a considerable option for future implementation.

Copyright Owner

Geesman, Ashley

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