Assessing Nitrogen Removal Efficacy in Planted Bioretention Mesocosms Subjected to Variable Stormwater Inflow
Open Access
- Author:
- Mattlin, Jacob
- Graduate Program:
- Horticulture
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- June 24, 2021
- Committee Members:
- Margaret Crowley Hoffman, Thesis Advisor/Co-Advisor
Lauren Mc Phillips, Committee Member
Erin Connolly, Program Head/Chair
James C Sellmer, Committee Member
Hong Wu, Committee Member - Keywords:
- Bioswale
Green Infrastructure
Saturated Zone
Drought
Phytoremediation - Abstract:
- Nitrate is a top polluter of waterways and a continuous problem in urban runoff. Green infrastructure (GI) is a modern technology used in urban systems to remediate runoff and reduce its inflow back into natural systems. Various parameters impact green infrastructure efficacy, but this experiment investigated plant selection, saturated zones, and drought conditions as key factors for nitrate scrubbing in GI. A six-month long greenhouse study was conducted to investigate Carex comosa, Symphyotrichum novi-belgii, and Pycnanthemum virginianum in GI mesocosms with and without saturated zones and later with a prolonged drought treatment. By the end of the pre-drought period, Carex comosa removed significantly more nitrate than Symphyotrichum novi-belgii (p= 0.001) and notably better nitrate removal than Pycnanthemum virginianum (p=0.076) in effluent water. Saturated zones increased nitrate removal overall (p < 0.001), but not by the final sampling event when considering each event individually (p> 0.05). Drought had a significant effect on percent nitrate removal (p= 0.017), however there were no significant benefits from saturated zones overall during the drought period (p= 0.699), with few exceptions. The exception was Carex comosa, where in the final drought the saturated zones showed great improvement in percent nitrate removal (p= 0.013). Saturated zones may be less beneficial long term for nitrate removal in highly wet environments. Further research is needed to study plants similar in growth and habit to Carex comosa for their potential use in GI.