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Hydraulic Response and Nitrogen Retention in Bioretention Mesocosms with Regulated Outlets: Part II—Nitrogen Retention
Author(s) -
Lucas William C.,
Greenway Margaret
Publication year - 2011
Publication title -
water environment research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.356
H-Index - 73
eISSN - 1554-7531
pISSN - 1061-4303
DOI - 10.2175/106143011x12989211840936
Subject(s) - bioretention , mesocosm , hydraulic retention time , nitrogen , water retention , environmental science , environmental engineering , retention time , retention basin , environmental chemistry , chemistry , stormwater , surface runoff , effluent , nutrient , soil water , ecology , soil science , biology , chromatography , organic chemistry
We observed dissolved nitrogen retention in vegetated bioretention mesocosms using different media with varying hydraulic conductivities. Elevated outlets were installed to regulate hydraulic response, with one treatment left free draining. The treatments (three replicates each) were loaded weekly with 50 cm of effluent averaging 2.47 mg/L nitrogen oxides (NO x ) and 4.67 mg/L total nitrogen for 1 year. The NO x and total nitrogen retention by the outlet regulated treatments was significantly greater than the unregulated treatment. The systems then were dosed 6 times with 53 cm of synthetic stormwater averaging 0.77 mg/L NO x and 1.46 mg/L total nitrogen, applied over 90 minutes. The outlet regulated treatment retained 68% NO x and 60% total nitrogen, while the corresponding free draining treatment retained 25% NO x and 27% total nitrogen. Over the following winter, the outlet regulated treatment retained 50% NO x and 73% total nitrogen, while the corresponding free draining treatment exported 17% more NO x , while retaining 50% total nitrogen.