Performance of Nitrogen-Removing Bioretention Systems for Control of Agricultural Runoff

Ergas, Sarina J.; Sengupta, Sukalyan; Siegel, Ryan; Pandit, Arka; Yao, Yifu; Yuan, Xin

doi:10.1061/(asce)ee.1943-7870.0000243

Cited by 52 publications

(24 citation statements)

References 29 publications

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“…Selected media types for treating stormwater runoff often include mixtures of sand and lignocellulosic media (FAWB, 2008), while up to 100% lignocellulosic (or elemental sulfur) media have been used for treating agricultural runoff and septic drainage Ergas et al, 2010). Stormwater denitrifying biofilters normally include sand rather than gravel media presumably because higher mass transfer rates occur in sand compared to gravel media; however, gravel media could be used to increase filtration rates and convey a greater volume of runoff.…”

Section: Introductionmentioning

confidence: 98%

Performance and Longevity of Denitrifying Wood-Chip Biofilters for Stormwater Treatment: A Microcosm Study

Lynn

YehDaniel

ErgasSarina

2015

Environmental Engineering Science

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Stormwater biofiltration systems can alleviate eutrophication by reducing nitrogen loadings from stormwater runoff. These systems can be modified to further enhance nitrogen removal by incorporating a submerged layer with a carbon source to promote denitrification. The objectives of this research were to compare the nitrate (NO À 3 ) removal performance of various media mixtures under varying environmental conditions and to estimate the longevity of carbon media in denitrifying biofilter microcosms. Media types evaluated consisted of mixtures containing sand, gravel, and/or eucalyptus wood chips. Negligible NO À 3 removal and high concentrations of total Kjeldahl nitrogen (TKN), phosphate (PO 3 À 4 ), and dissolved organic carbon (DOC) were observed from carbon-containing media that were left unsaturated before analysis. High removal of NO À 3 (85-100%) and low concentrations of TKN and DOC were observed when carbon-containing media were acclimated under saturated conditions. A mixture of gravel and eucalyptus-wood media exhibited high NO À 3 removal rates, low final DOC concentrations, and was selected for further analysis. Results indicated that carbon-containing biofilters should include gravel instead of sand media and be designed to maintain saturation to increase NO À 3 removal rates and decrease TKN, PO 3 À 4 , and DOC export. Results from the gravel-wood media were then imported into a novel model developed to estimate media longevity. Based on observed DOC dissolution rate, estimated longevity of the gravel-wood media in denitrifying biofilters was greater than a decade. Results indicate that permanently saturated carbon-containing media will supply a sustainable source of carbon over the functional lifespan of stormwater biofilters.

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Section: Introductionmentioning

confidence: 98%

Performance and Longevity of Denitrifying Wood-Chip Biofilters for Stormwater Treatment: A Microcosm Study

Lynn

YehDaniel

ErgasSarina

2015

Environmental Engineering Science

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“…While S o -based denitrification has been studied previously (e.g., Batchelor and Lawrence, 1978;Hasegawa et al, 2004;Moon et al, 2003;and Davidson and Cormack, 1993;Sengupta et al, 2007;Ergas et al, 2010) there is little information on S o -based denitrification for modern BNR processes. Startup time and backwashing needs are not known.…”

Section: Objectivesmentioning

confidence: 97%

Elemental Sulfur (S°) as a Supplemental Electron Donor for Wastewater Denitrification

Wang¹,

Pavissich²,

Sabba³

et al. 2011

proc water environ fed

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Many utilities are seeking more cost effective, safe, and reliable electron donors for biological nutrient removal (BNR). Elemental sulfur (S o ) may be an attractive option, but little is known about the feasibility of S o -based denitrification and its kinetics. In this research, we used benchscale, S o packed-bed reactors to determine denitrification fluxes as a function of bulk concentrations. Both nitrate and nitrite were removed after 30-50 days. Maximum fluxes were 0.8 gN/m 2 -day to 1 gN/m 2 -day. As biofilm thickness increased over time, maximum fluxes increased. However, fluxes for low nitrate condition decreased, providing an increase in the apparent K S for nitrate. Reactors maintained sustained high fluxes for over 140 days, without any backwashing. However, when a vigorous backwashing was carried out, all the biomass was lost and the reactor needed a 30-day period to return to previous fluxes. Results suggest that biomass production is slow, as expected for an autotrophic system, but that reasonably high denitrification fluxes can be obtained. Care must be taken not to remove excessive biomass during backwashing.

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“…Several studies have investigated processes that occur in denitrifying biofilters during rainfall events (Dietz and Clausen, 2006;Smith, 2008;and Ergas et al, 2010;Lucas and Greenway, 2011;Lee et al, 2013). However, processes that occur in denitrifying biofilters during ADCs can also affect water quality performance.…”

Section: Introductionmentioning

confidence: 96%

Performance of Denitrifying Stormwater Biofilters Under Intermittent Conditions

Lynn

YehDaniel

ErgasSarina

2015

Environmental Engineering Science

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Denitrifying stormwater biofiltration systems that include submerged zones containing organic carbon sources can alleviate eutrophication by reducing nitrogen loadings from stormwater runoff. The objective of this research was to evaluate performance of denitrifying biofilters containing wood chip medium under varying dynamic loading rates and antecedent dry conditions (ADCs). Results showed that during ADCs, dissolved organic carbon (DOC) concentrations increased in pore water due to dissolution of the wood chip medium. During a storm event, nitrate (NO 3 -) removal was enhanced due to high pore water DOC concentrations and mixing of NO 3 -from the influent with pore water; however, as DOC was gradually flushed out of the biofilter, higher effluent NO 3 -concentrations were observed over time. At lower hydraulic loading rates, effluent NO 3 -concentrations were low due to sufficient hydraulic residence time for denitrification. For all storm events tested, an overall NO 3 -mass removal efficiency of 85% was achieved. Sulfate reduction was observed at long ADCs (up to 30 days). Phosphate release was observed when NO 3 -was absent from the effluent, possibly due to dissolution of iron oxyhydroxides under low redox conditions. Findings from this study are being used to develop a mathematical model of nitrogen removal in denitrifying stormwater biofilters.

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Performance of Nitrogen-Removing Bioretention Systems for Control of Agricultural Runoff

Cited by 52 publications

References 29 publications

Performance and Longevity of Denitrifying Wood-Chip Biofilters for Stormwater Treatment: A Microcosm Study

Performance and Longevity of Denitrifying Wood-Chip Biofilters for Stormwater Treatment: A Microcosm Study

Elemental Sulfur (S°) as a Supplemental Electron Donor for Wastewater Denitrification

Performance of Denitrifying Stormwater Biofilters Under Intermittent Conditions

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