Changes

*[https://www3.epa.gov/region1/npdes/stormwater/research/epa-final-report-filter-study.pdf (USEPA, 2013) - Evaluation and Optimization of Bioretention Design for Nitrogen and Phosphorus Removal]

*[https://www3.epa.gov/region1/npdes/stormwater/research/epa-final-report-filter-study.pdf (USEPA, 2013) - Evaluation and Optimization of Bioretention Design for Nitrogen and Phosphorus Removal]

**USEPA conducted both field and laboratory testing on the performance of bioretention with augmented designs and filter media composition with aluminum hydroxide/oxide content, found normally within water treatment residuals. These additives added at 10-15% of the total filter media mix ad median removal efficiencies of 90-99% of orthophosphate and a second study found a bioretention design with WTR mixture in the filter media and a [[Bioretention: Internal water storage|IWSZ]] optimized to remove phosphorus and nitrogen had a removal efficiency of 20% and effluent concentrations below 20µg/L (well below the MECP/CCME guideline in Ontario).

**USEPA conducted both field and laboratory testing on the performance of bioretention with augmented designs and filter media composition with aluminum hydroxide/oxide content, found normally within water treatment residuals. These additives added at 10-15% of the total filter media mix ad median removal efficiencies of 90-99% of orthophosphate and a second study found a bioretention design with WTR mixture in the filter media and a [[Bioretention: Internal water storage|IWSZ]] optimized to remove phosphorus and nitrogen had a removal efficiency of 20% and effluent concentrations below 20µg/L (well below the MECP/CCME guideline in Ontario).

[[File:EBC vs. TBC.PNG|500px|thumb| Comparison of an Enhanced dephosphorization bioretention cell (EBC) (above) vs. a traditional bioretention cell (TBC) (below). The EBC includes evenly spaced apart soil mixture layers, which includes 70-80% native soil found on site mixed with 20-30% of charcoal, oregani matter and iron, along with permeable layers of gravel pumice and zeolite, all of which help adsorb phosphates out of stormwater entering the system. This differs from the TBC design which generally includes just a gravel bed to aid in the facility's drainage ability (Ho and Lin, 2022)<ref>Ho, C.C. and Lin, Y.X., 2022. Pollutant Removal Efficiency of a Bioretention Cell with Enhanced Dephosphorization. Water, 14(3), p.396. https://mdpi-res.com/books/book/5900/Urban_Runoff_Control_and_Sponge_City_Construction.pdf?filename=Urban_Runoff_Control_and_Sponge_City_Construction.pdf#page=168</ref>.]]

[[File:EBC vs. TBC.PNG|500px|thumb| Comparison of an Enhanced dephosphorization bioretention cell (EBC) (above) vs. a traditional bioretention cell (TBC) (below). The EBC includes evenly spaced apart soil mixture layers, which includes 70-80% native soil found on site mixed with 20-30% of charcoal, oregani matter and iron, along with permeable layers of gravel pumice and zeolite, all of which help adsorb phosphates out of stormwater entering the system. This differs from the TBC design which generally includes just a gravel bed to aid in the facility's drainage ability (Ho and Lin, 2022)<ref>Ho, C.C. and Lin, Y.X., 2022. Pollutant Removal Efficiency of a Bioretention Cell with Enhanced Dephosphorization. Water, 14(3), p.396. https://mdpi-res.com/books/book/5900/Urban_Runoff_Control_and_Sponge_City_Construction.pdf?filename=Urban_Runoff_Control_and_Sponge_City_Construction.pdf#page=168</ref>.]]

*[https://www.mdpi.com/2073-4441/14/3/396 (Ho and Lin, 2022) - Pollutant Removal Efficiency of a Bioretention Cell with Enhanced Dephosphorization]

*[https://www.mdpi.com/2073-4441/14/3/396 (Ho and Lin, 2022) - Pollutant Removal Efficiency of a Bioretention Cell with Enhanced Dephosphorization]

**Authors Ho and Lin, 2022 note that bioretention practices perform poorly in reducing phosphorus from influent stormwater when compared to their ability to remove ammonia and COD pollutants. The authors tested a new type of enhanced dephosphorization bioretention cell (EBC) which improves phosphorus removal performance. The difference between EBC and a traditional bioretention cell is that the lowest level of an EBC feature is comprised of a mixed fill material layer (permeable layers - PLs and soil mixed layers - SMLs) instead of a traditional gravel bed layer. The SMLs include active charcoal powder, organic matter and iron, evenly spaced apart, while the PLs include aggregates of gravel, pumice and zeolite. Over the two years that the same sized EBC feature was monitored in comparison to a standard bioretention cell they found that the EBC outperformed the traditional bioretention cell by removing 92% of total phosphorus to 52%. The average inflow concentration for both features from May 2019 - April 2021 was 0.76 mg/L, whereas the outflow concentration averages were 0.36 mg/L for the traditional bioretention cell and 0.06 mg/L for the EBC, respectively (Ho and Lin, 2022)<ref>Ho, C.C. and Lin, Y.X., 2022. Pollutant Removal Efficiency of a Bioretention Cell with Enhanced Dephosphorization. Water, 14(3), p.396. https://mdpi-res.com/books/book/5900/Urban_Runoff_Control_and_Sponge_City_Construction.pdf?filename=Urban_Runoff_Control_and_Sponge_City_Construction.pdf#page=168</ref>.

**Authors Ho and Lin, 2022 note that bioretention practices perform poorly in reducing phosphorus from influent stormwater when compared to their ability to remove ammonia and COD pollutants. The authors tested a new type of enhanced dephosphorization bioretention cell (EBC) which improves phosphorus removal performance. The difference between EBC and a traditional bioretention cell is that the lowest level of an EBC feature is comprised of a mixed fill material layer (permeable layers - PLs and soil mixed layers - SMLs) instead of a traditional gravel bed layer. The SMLs include active charcoal powder, organic matter and iron, evenly spaced apart, while the PLs include aggregates of gravel, pumice and zeolite. Over the two years that the same sized EBC feature was monitored in comparison to a standard bioretention cell they found that the EBC outperformed the traditional bioretention cell by removing 92% of total phosphorus to 52%. The average inflow concentration for both features from May 2019 - April 2021 was 0.76 mg/L, whereas the outflow concentration averages were 0.36 mg/L for the traditional bioretention cell and 0.06 mg/L for the EBC, respectively (Ho and Lin, 2022)<ref>Ho, C.C. and Lin, Y.X., 2022. Pollutant Removal Efficiency of a Bioretention Cell with Enhanced Dephosphorization. Water, 14(3), p.396. https://mdpi-res.com/books/book/5900/Urban_Runoff_Control_and_Sponge_City_Construction.pdf?filename=Urban_Runoff_Control_and_Sponge_City_Construction.pdf#page=168</ref>.

*[https://sustainabletechnologies.ca/app/uploads/2019/06/improving-nutrient-retention-in-bioretention-tech-brief.pdf (STEP, 2019) - Improving nutrient retention in bioretention - Technical Brief]

*[https://sustainabletechnologies.ca/app/uploads/2019/06/improving-nutrient-retention-in-bioretention-tech-brief.pdf (STEP, 2019) - Improving nutrient retention in bioretention - Technical Brief]

**STEP researchers developed a study to examine the effectiveness of reactive media amendments as a means of enhancing phosphorus retention in a bioretention cell draining a 1150 m² parking lot in the City of Vaughan. For testing purposes, the bioretention was divided into three hydrologically distinct cells: (1) with a high sand, low phosphorus media mix (control); (2) with a proprietary reactive media (Sorbitve™) mixed into the sandy filter media, and (3) with a 170 cm layer of iron rich sand (aka red sand) below the sandy filter media. Outflow quantity and quality from each cell was measured directly, while inflows and runoff quality were estimated based on monitoring of an adjacent asphalt reference site over the same time period. The results found that the Sorbitve™ and the Iron rich (red) sand cells had lower concentrations of Total Phosphorus (among other contaminants) in its effluent outflow, and the TP measured was below the CCDME guideline of 0.03mg/L in both years monitored for Sorbitve™ (2016 & 2017) and 2017 for the cell with Iron rich (red) sand. Both cells had median concentrations lower than the control media cell used in the study by at least 68% for TP (STEP, 2019<ref>STEP. 2019. Improving nutrient retention in bioretention - Technical Brief. Prepared by Toronto and Region Conservation Authority. Published in 2018. https://sustainabletechnologies.ca/app/uploads/2019/06/improving-nutrient-retention-in-bioretention-tech-brief.pdf</ref>.

**STEP researchers developed a study to examine the effectiveness of reactive media amendments as a means of enhancing phosphorus retention in a bioretention cell draining a 1150 m² parking lot in the City of Vaughan. For testing purposes, the bioretention was divided into three hydrologically distinct cells: (1) with a high sand, low phosphorus media mix (control); (2) with a proprietary reactive media (Sorbitve™) mixed into the sandy filter media, and (3) with a 170 cm layer of iron rich sand (aka red sand) below the sandy filter media. Outflow quantity and quality from each cell was measured directly, while inflows and runoff quality were estimated based on monitoring of an adjacent asphalt reference site over the same time period. The results found that the Sorbitve™ and the Iron rich (red) sand cells had lower concentrations of Total Phosphorus (among other contaminants) in its effluent outflow, and the TP measured was below the CCDME guideline of 0.03mg/L in both years monitored for Sorbitve™ (2016 & 2017) and 2017 for the cell with Iron rich (red) sand. Both cells had median concentrations lower than the control media cell used in the study by at least 68% for TP (STEP, 2019<ref>STEP. 2019. Improving nutrient retention in bioretention - Technical Brief. Prepared by Toronto and Region Conservation Authority. Published in 2018. https://sustainabletechnologies.ca/app/uploads/2019/06/improving-nutrient-retention-in-bioretention-tech-brief.pdf</ref>.

*[https://repository.library.noaa.gov/view/noaa/41705/noaa_41705_DS1.pdf (Ament, et al. 2022) - Phosphorus removal, metals dynamics, and hydraulics in stormwater bioretention systems amended with drinking water treatment residuals]

*[https://repository.library.noaa.gov/view/noaa/41705/noaa_41705_DS1.pdf (Ament, et al. 2022) - Phosphorus removal, metals dynamics, and hydraulics in stormwater bioretention systems amended with drinking water treatment residuals]

**Researchers from the University of Minnesota, the University of Vermont and the USEPA, conducted field experiment to test the effectiveness of Drinking water treatment residuals (DWTRs) as a filter media amendment additive for improve Total Phosphorus (TP) removal in roadside bioretention features. Influent phosphorus levels was relatively low when compared to normal influent stormwater P levels (dissolved = 0.002 mg/L, soluble reactive = 0.022, particulate = 0.036 mg/L) but the difference between the bioretention cell in the study with DWTR additives and the control bioretention cells were 95% (Large D.A) - 97% (small D.A) TP removal and 79 (large D.A)and 91% (small D.A) respectively. The outflows were well below the CCME guidelines of 0.3 mg/L coming in at 0.010 mg/L (large D.A) and 0.011mg/L (small D.A) (Ament, et al. 2022)<ref>Ament, M.R., Roy, E.D., Yuan, Y. and Hurley, S.E., 2022. Phosphorus removal, metals dynamics, and hydraulics in stormwater bioretention systems amended with drinking water treatment residuals. Journal of Sustainable Water in the Built Environment, 8(3), p.04022003.</ref>.)

**Researchers from the University of Minnesota, the University of Vermont and the USEPA, conducted field experiment to test the effectiveness of Drinking water treatment residuals (DWTRs) as a filter media amendment additive for improve Total Phosphorus (TP) removal in roadside bioretention features. Influent phosphorus levels was relatively low when compared to normal influent stormwater P levels (dissolved = 0.002 mg/L, soluble reactive = 0.022, particulate = 0.036 mg/L) but the difference between the bioretention cell in the study with DWTR additives and the control bioretention cells were 95% (Large D.A) - 97% (small D.A) TP removal and 79 (large D.A)and 91% (small D.A) respectively. The outflows were well below the CCME guidelines of 0.3 mg/L coming in at 0.010 mg/L (large D.A) and 0.011mg/L (small D.A) (Ament, et al. 2022)<ref>Ament, M.R., Roy, E.D., Yuan, Y. and Hurley, S.E., 2022. Phosphorus removal, metals dynamics, and hydraulics in stormwater bioretention systems amended with drinking water treatment residuals. Journal of Sustainable Water in the Built Environment, 8(3), p.04022003.</ref>.)

*[https://www.researchgate.net/publication/332063360_Enhanced_Nutrients_Removal_in_Bioretention_Systems_Modified_with_Water_Treatment_Residual_and_Internal_Water_Storage_Zone/download (Qiu, et al. 2019) - Enhanced Nutrients Removal in Bioretention Systems Modified with Water Treatment Residual and Internal Water Storage Zone]

*[https://www.researchgate.net/publication/332063360_Enhanced_Nutrients_Removal_in_Bioretention_Systems_Modified_with_Water_Treatment_Residual_and_Internal_Water_Storage_Zone/download (Qiu, et al. 2019) - Enhanced Nutrients Removal in Bioretention Systems Modified with Water Treatment Residual and Internal Water Storage Zone]