Civil Engineering ETDs

Publication Date

Fall 12-1-2021


The objective of this study was to determine whether the polyphosphate metabolism in purple photosynthetic bacteria (PPB) is similar to that of wastewater polyphosphate-accumulating organisms (PAOs) such as Accumulibacter. Dairy lagoon samples were studied in continuous and batch laboratory tests to evaluate whether cyclic light and dark conditions for PPB are similar to aerobic and anaerobic conditions for PAOs in domestic wastewater treatment systems. 16s rRNA gene amplicon sequencing indicated the presence of the purple sulfur bacterium Thiolamprovum (53.92%) in one lagoon source, and Thiodictyon (3.50%) in a second lagoon. Phosphorus contents were at least 0.7% higher than the typical 2% for microbial biomass, suggesting polyphosphate accumulation. Experimental measurements indicated phosphorus uptake and release under various conditions, although a link between phosphorus release and acetate uptake was not established. This work lays the groundwork for future research to determine specific conditions for PPB to improve phosphorus removal in lagoon systems.


purple bacteria, phosphorus removal, polyphosphate accumulating organisms, enhanced biological phosphorus removal

Document Type




Degree Name

Civil Engineering

Level of Degree


Department Name

Civil Engineering

First Committee Member (Chair)

Dr. Andrew Schuler

Second Committee Member

Dr. Jose Cerrato

Third Committee Member

Dr. David Hanson