Changes

* A field study in Maplewood, Minnesota used an iron-enhanced (5% iron filings) ditch check sand [[Filtration|filter]] for installation in [[Swales|swales]] to provide treatment of dissolved heavy metals and dissolved phosphorous in stormwater [[Runoff volume control target|runoff]] from highways (Ahmed at el., 2014) <ref>Ahmed, F., Natarajan, P., Gulliver, J., Weiss, P., Nieber, J. 2014. Assessing and Improving Pollution Prevention by Swales. https://www.lrrb.org/pdf/201430.pdf</ref>.

* A field study in Maplewood, Minnesota used an iron-enhanced (5% iron filings) ditch check sand [[Filtration|filter]] for installation in [[Swales|swales]] to provide treatment of dissolved heavy metals and dissolved phosphorous in stormwater [[Runoff volume control target|runoff]] from highways (Ahmed at el., 2014) <ref>Ahmed, F., Natarajan, P., Gulliver, J., Weiss, P., Nieber, J. 2014. Assessing and Improving Pollution Prevention by Swales. https://www.lrrb.org/pdf/201430.pdf</ref>.

* In Ajax, Ontario, iron filings were tested as an additive in [[Bioretention|bioretention]] areas and compared against two alternatives: a bioretention area with 5% sorbtive media, and a typical engineered media bed consisting of a shredded hardwood mulch layer over a sand–soil–organic mixture. Phosphorus concentrations were lowest in the sorbtive media mix, followed by the iron filing mix, while the typical media bed had the poorest removal performance (Aquafor Beech, 2018)<ref>Aquafor Beech Ltd. 2018. Monitoring Report (2015–2017): Rain Garden Performance Monitoring Program: Lake Driveway. https://www.ajax.ca/en/get-involved/resources/Stormwater/Rain-Garden-Performance-Monitoring-Program-Lake-Driveway.pdf</ref>.

* In Ajax, Ontario, iron filings were tested as an additive in [[Bioretention|bioretention]] areas and compared against two alternatives: a bioretention area with 5% sorbtive media, and a typical engineered media bed consisting of a shredded hardwood mulch layer over a sand–soil–organic mixture. Phosphorus concentrations were lowest in the sorbtive media mix, followed by the iron filing mix, while the typical media bed had the poorest removal performance (Aquafor Beech, 2018)<ref>Aquafor Beech Ltd. 2018. Monitoring Report (2015–2017): Rain Garden Performance Monitoring Program: Lake Driveway. https://www.ajax.ca/en/get-involved/resources/Stormwater/Rain-Garden-Performance-Monitoring-Program-Lake-Driveway.pdf</ref>.

[[File:Screenshot 2025-08-13 113919.png|500px|thumb|[[Bioretention]] schematic, with circles highlighting ZVI addition and phosphorus removal (Lechner, 2016)<ref name = Lechner>Lechner L. 2016. Phosphorus Removal From Stormwater Using Zero-Valent Iron. Applied Science Masters Thesis.</ref>.]]

[[File:Screenshot 2025-08-13 113919.png|500px|thumb|[[Bioretention]] schematic, with circles highlighting ZVI addition and phosphorus removal (Lechner, 2016)<ref name = Lechner>Lechner L. 2016. Phosphorus Removal From Stormwater Using Zero-Valent Iron. Applied Science Masters Thesis.</ref>.]].

===Benefits===

===Benefits===