Date of Completion


Document Type

Honors College Thesis

Thesis Type

Honors College

First Advisor

Eric Roy

Second Advisor

Stephanie Hurley

Third Advisor

Joshua Faulkner


Nitrogen, Bioretention, Green Stormwater Infrastructure, Drinking Water Treatment Residuals


Urban stormwater runoff transports a suite of environmental pollutants that can degrade the quality of receiving waters. Bioretention cells, a type of engineered raingarden, have been shown to reduce runoff volumes and remove a variety of pollutants. The ability of conventional bioretention cells to remove nitrogen and phosphorus, however, is variable and bioretention soil media can act as a net exporter of nutrients. This is concerning as excess loading of nitrogen and phosphorus can lead to eutrophication of surface waters. Drinking water treatment residuals (DWTR), metal (hydr)oxide rich byproducts of the drinking water treatment process, have been studied as an amendment to bioretention soil media due to their high phosphorus sorption capacity. However, very few studies have explicitly addressed the effects that DWTRs may have on nitrogen cycling within bioretention cells. This research investigates any potential benefits or tradeoffs that DWTR amendment has on nitrogen removal in bioretention cells. The capacity for DWTRs to either retain or leach dissolved inorganic nitrogen was tested in the laboratory, and a full-scale field experiment was conducted where DWTR amended bioretention cells and experimental Controls were monitored for influent and effluent nitrogen concentrations over two years. The results of this thesis show that the DWTRs tested have little to no effect on the transformation and removal of nitrogen in bioretention cells.

Creative Commons License

Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License.

Available for download on Tuesday, May 17, 2022