Long-term field performance of a conventional and modified bioretention system for removing dissolved nitrogen species in stormwater runoff

WATER RESEARCH

卷:170

Article

Lopez-Ponnada, Emma, V¹  Lynn, Thomas J.²  Ergas, Sarina J.¹  Mihelcic, James R.¹ 

[1] Univ S Florida, Dept Civil & Environm Engn, 4202 E Fowler Ave,ENB 118, Tampa, FL 33620 USA

[2] Texas A&M Univ Kingsville, Dept Environm Engn, 700 Univ Blvd,MSC 213, Kingsville, TX 78363 USA

关键词: Biological nutrient removal;    Nitrogen;    Urbanization;    Green stormwater infrastructure;    Low impact development;    Stormwater BMP;   

DOI  :  10.1016/j.watres.2019.115336

来源: Elsevier

【 摘 要 】

Bioretention systems are efficient at removing particulates, metals, and hydrocarbons from stormwater runoff. However, managing dissolved nitrogen (N) species (dissolved organic N, NH4+, NO2-, NO3-) is a challenge for these systems. This paper reports the results of a long-term field study comparing N removal of: 1) a modified bioretention system that included an internal water storage zone containing wood chips to promote denitrification and 2) a conventional bioretention system. The systems were studied, without and with plants, under varying hydraulic loading rates (HLRs) and antecedent dry conditions (ADCs). Both bioretention designs were efficient at removing NH4+(83% modified, 74% conventional), while removal of NOx (NO2--N + NO3--N) was significantly higher in the modified system (81% modified, 29% conventional). Results show that the addition of an internal water storage zone promotes denitrification, resulting in lower effluent TN concentrations (<0.75 mg/L modified, similar to 1.60 mg/L conventional). The lowest HLR studied, 4.1 cm/h, provided the longest hydraulic retention time in the internal water storage zone (similar to 3 h) and had the greatest TN removal efficiency (90% modified, 59% conventional). In contrast to prior short-term studies, ADCs between 0 and 13 days did not significantly affect DOC export or TN removal. A short-term study with Florida friendly vegetation indicated that TN removal performance was enhanced in the conventional bioretention system. This field study provides promising results for improving dissolved N removal by modifying bioretention systems to include an internal water storage zone containing wood chips. (C) 2019 Published by Elsevier Ltd.

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