Understanding Urban Stormwater Denitrification in Bioretention Internal Water Storage Zones


Autoria(s): Igielski, Sara Jasmine
Contribuinte(s)

Davis, Allen P

Digital Repository at the University of Maryland

University of Maryland (College Park, Md.)

Civil Engineering

Data(s)

15/09/2016

15/09/2016

2016

Resumo

Free-draining bioretention systems commonly demonstrate poor nitrate removal. In this study, column tests verified the necessity of a permanently saturated zone to target nitrate removal via denitrification. Experiments determined a first-order denitrification rate constant of 0.0011 min-1 specific to Willow Oak woodchip media. A 2.6-day retention time reduced 3.0 mgN/L to below 0.05 mg-N/L. During simulated storm events, hydraulic retention time may be used as a predictive measurement of nitrate fate and removal. A minimum 4.0 hour retention time was necessary for in-storm denitrification defined by a minimum 20% nitrate removal. Additional environmental parameters, e.g., pH, temperature, oxidation-reduction potential, and dissolved oxygen, affect denitrification rate and response, but macroscale measurements may not be an accurate depiction of denitrifying biofilm conditions. A simple model was developed to predict annual bioretention nitrate performance. Novel bioretention design should incorporate bowl storage and large subsurface denitrifying zones to maximize treatment volume and contact time.

Identificador

doi:10.13016/M20B84

http://hdl.handle.net/1903/18824

Idioma(s)

en

Palavras-Chave #Environmental engineering #Civil engineering #bioretention #denitrification #nitrogen
Tipo

Thesis