Changes

==Design and Maintenance considerations==

==Design and Maintenance considerations==

The mechanisms for phosphorus removal are sedimentation, [[filtration]], adsorption, [[precipitation]], and [[Plants#Plant Characteristics|plant uptake]]. Particulate phosphorus can be removed through sedimentation and filtration and is often trapped among other solids within a shallow depth at the media surface (Hsieh et al. 2007<ref name="example3">Hsieh, C.-H., Davis, A. P., and Needelman, B. A. (2007).“Bioretentioncolumn studies of phosphorus removal from urban stormwater runoff.” Water Environ. Res., 79(2), 177–184.</ref>). Dissolved phosphorus is removed deeper in the media as it requires higher retention time (Hsieh et al. 2007<ref name="example3" />). Hunt et al. (2006)<ref name="example4">Hunt, W. F., Jarrett, A. R., Smith, J. T., and Sharkey, L. J. (2006).“Evalu-ating bioretention hydrology and nutrient removal at three field sites in North Carolina.” J. Irrig. Drain. Eng., 132(6), 600–608.</ref>, suggested a minimum depth of 0.6m and recommends 0.9m and infiltration rate of 0.007- 0.028 mm/s (1-4 in/h) for targeted removal of dissolved phosphorus. Removal of dissolved phosphorus relies heavily on the specifications of the LID media, it’s phosphorus content, type and percentage of organic matter, its potential hydrogen (pH), and temperature.

The mechanisms for phosphorus removal are sedimentation, filtration, adsorption, [[Understanding rainfall statistics|precipitation]], and [[Plants#Plant Characteristics|plant uptake]]. Particulate phosphorus can be removed through sedimentation and filtration and is often trapped among other solids within a shallow depth at the media surface (Hsieh et al. 2007<ref name="example3">Hsieh, C.-H., Davis, A. P., and Needelman, B. A. (2007).“Bioretentioncolumn studies of phosphorus removal from urban stormwater runoff.” Water Environ. Res., 79(2), 177–184.</ref>). Dissolved phosphorus is removed deeper in the media as it requires higher retention time (Hsieh et al. 2007<ref name="example3" />). Hunt et al. (2006)<ref name="example4">Hunt, W. F., Jarrett, A. R., Smith, J. T., and Sharkey, L. J. (2006).“Evalu-ating bioretention hydrology and nutrient removal at three field sites in North Carolina.” J. Irrig. Drain. Eng., 132(6), 600–608.</ref>, suggested a minimum depth of 0.6m and recommends 0.9m and infiltration rate of 0.007- 0.028 mm/s (1-4 in/h) for targeted removal of dissolved phosphorus. Removal of dissolved phosphorus relies heavily on the specifications of the LID media, it’s phosphorus content, type and percentage of organic matter, its potential hydrogen (pH), and temperature.

Media with high phosphorus content provides additional support for plant growth, however it will harm the phosphorus removal capability of the feature (Hunt et al. 2006)<ref name="example4" />). Similarly high percentage of organic matter in the media can increase the phosphorus content after degradation and lead to leaching of phosphorus (Clark and Pitt 2009<ref>Clark, S. E., and Pitt, R. (2009).“Storm-water filter media pollutantretention under aerobic versus anaerobic conditions.” J. Environ.Eng., 135(5), 367–371.</ref>). Different types of organic matter have various degrees of phosphorus leaching. To ensure that an LID can provide phosphorus removal, the phosphorus content and percentage of organic matter must be carefully selected and implemented during construction. For proper ranges of these values refer to the [[Bioretention: Filter media|bioretention media page]]. The suggested ranges should be met during the design phase and inspected before assumption of the feature.

Media with high phosphorus content provides additional support for plant growth, however it will harm the phosphorus removal capability of the feature (Hunt et al. 2006)<ref name="example4" />). Similarly high percentage of organic matter in the media can increase the phosphorus content after degradation and lead to leaching of phosphorus (Clark and Pitt 2009<ref>Clark, S. E., and Pitt, R. (2009).“Storm-water filter media pollutantretention under aerobic versus anaerobic conditions.” J. Environ.Eng., 135(5), 367–371.</ref>). Different types of organic matter have various degrees of phosphorus leaching. To ensure that an LID can provide phosphorus removal, the phosphorus content and percentage of organic matter must be carefully selected and implemented during construction. For proper ranges of these values refer to the [[Bioretention: Filter media|bioretention media page]]. The suggested ranges should be met during the design phase and inspected before assumption of the feature.