Changes

A maintenance strategy common to all types of LID practices to avoid nutrient leaching is annual removal of accumulated sediment and debris from inlets.  For bioretention cells, bioswales and stormwater tree trenches featuring surface inlets and soil media, periodic removal of the top 2 to 5 centimetres of media in areas adjacent to inlets, and replacement with material that meets design specifications (e.g., every two years) has also been recommended.<ref> Johnson, J.P., Hunt, W.F. 2016. Evaluating the spatial distribution of pollutants and associated maintenance requirements in an 11 year-old bioretention cell in urban Charlotte, NC. Journal of Environmental Management. 184 (2016):363-370. https://www.sciencedirect.com/science/article/pii/S0301479716307812 </ref> <ref>Jones, P.S., Davis, A.P. 2013. Spatial Accumulation and Strength of Affiliation of Heavy Metals in Bioretention Media. Journal of Environmental Engineering. 139(4): 479-487. https://ascelibrary.org/doi/abs/10.1061/%28ASCE%29EE.1943-7870.0000624 </ref>

A maintenance strategy common to all types of LID practices to avoid nutrient leaching is annual removal of accumulated sediment and debris from inlets.  For bioretention cells, bioswales and stormwater tree trenches featuring surface inlets and soil media, periodic removal of the top 2 to 5 centimetres of media in areas adjacent to inlets, and replacement with material that meets design specifications (e.g., every two years) has also been recommended.<ref> Johnson, J.P., Hunt, W.F. 2016. Evaluating the spatial distribution of pollutants and associated maintenance requirements in an 11 year-old bioretention cell in urban Charlotte, NC. Journal of Environmental Management. 184 (2016):363-370. https://www.sciencedirect.com/science/article/pii/S0301479716307812 </ref> <ref>Jones, P.S., Davis, A.P. 2013. Spatial Accumulation and Strength of Affiliation of Heavy Metals in Bioretention Media. Journal of Environmental Engineering. 139(4): 479-487. https://ascelibrary.org/doi/abs/10.1061/%28ASCE%29EE.1943-7870.0000624 </ref>

==Enhanced Phosphorous Removal==

==Additives for Enhanced Phosphorous Removal==

Particulate phosphorus is removed to a good extent in LIDs due to the sedimentation and filtration mechanisms offered by these features. To further improve the removal of total phosphorus, the removal of dissolved phosphorus is targeted. As explained in the previous section, adsorption is the main removal mechanism for dissolved phosphorus and aluminum and iron are the main sorptive elements.  Therefore, including [[Additives| additives]] in filter media blends can enhance phosphorus retention.  Examples of such [[Additives| additives]] are [[Iron filings (ZVI)|iron filings]] or zero valent iron, iron-enriched or [[red sand|“red” sand]], and [[water treatment residuals]]. Other [[Additives| additives]] that enhance filter media sorption capacity are [[biochar]], [[Bold & Gold]], [[Smart Sponge]], and [[sorbtive media| Sorbtive Media]].

Particulate phosphorus is removed to a good extent in LIDs due to the sedimentation and filtration mechanisms offered by these features. To further improve the removal of total phosphorus, the removal of dissolved phosphorus is targeted. As explained in the previous section, adsorption is the main removal mechanism for dissolved phosphorus and aluminum and iron are the main sorptive elements.  Therefore, including [[Additives| additives]] in filter media blends can enhance phosphorus retention.  Examples of such [[Additives| additives]] are [[Iron filings (ZVI)|iron filings]] or zero valent iron, iron-enriched or [[red sand|“red” sand]], and [[water treatment residuals]]. Other [[Additives| additives]] that enhance filter media sorption capacity are [[biochar]], [[Bold & Gold]], [[Smart Sponge]], and [[sorbtive media| Sorbtive Media]]. Determining when additive enhanced filter media needs replacing or maintenance represents a new challenge for stormwater asset managers, as there are no suitable visual indicators.  Erickson et al. (2018) suggest effluent sampling and laboratory testing to identify when enhanced filter media pollutant retention is waning, or periodic sampling and batch (laboratory) testing of filter media to directly measure its capacity to retain the targeted pollutants.<ref>Erickson, A.J., Taguchi, V.J., Gulliver, J.S. 2018. The Challenge of Maintaining Stormwater Control Measures: A Synthesis of Recent Research and Practitioner Experience. Sustainability. 2018, 10, 3666. https://www.mdpi.com/2071-1050/10/10/3666 </ref>

==References==

==References==

[[Category:Phosphorus]]

[[Category:Phosphorus]]

[[Category: Water quality]]

[[Category: Water quality]]