Bold & Gold

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What is it?

Bold & Gold is a biosorption activated media (BAM) for pollution control developed by the Stormwater Management Academy at the University of Central Florida. It can be used to achieve nitrogen and phosphorus reduction in stormwaterSurface runoff from at-grade surfaces, resulting from rain or snowmelt events., wastewater and agricultural applications such as retention basinsGround depression acting as a flow control and water treatment structure, that is normally dry., swales and rain gardens, urban gardens and soil cells, permeable paving, green roofs, filter strips and more. Bold & Gold is composed of a patented blend of mineral materials, sandMineral particles which are smaller than 2 mm, and which are free of appreciable quantities of clay and silt. Coarse sand usually designates sand grains with particle size between 0.2 and 0.02 mm., and clay1. A mineral soil separate consisting of particles less than 0.002 millimeter in equivalent diameter. 2. A soil texture class. 3. (Engineering) A fine-grained soil (more than 50 percent passing the No. 200 Sieve) that has a high plasticity index in relation to the liquid limit. (Unified Soil Classification System)..

How is it being used?

Bold & Gold FiltrationThe technique of removing pollutants from runoff as it infiltrates through the soil. Media is currently being used in experimental projects in North Carolina to evaluate nutrient reduction capabilities. No projects that used Bold & Gold were found in Ontario, however, it has been used for projects such as an upflow filter chamber following a detentionThe temporary storage of stormwater to control discharge rates, and allow for sedimentation. pondA body of water smaller than a lake, often artificially formed., a commercial green roofA thin layer of vegetation and growing medium installed on top of a conventional flat or sloped roof, also referred to as living roofs or rooftop gardens. in Florida, and a subsurface upflow wetlandA vegetated area such as a bog, fen, marsh, or swamp, where the soil or root zone is saturated for part of the year. filter for nutrient removal. [1] FiltrationThe technique of removing pollutants from runoff as it infiltrates through the soil. Media Specifications and Typical Cross Sections are provided on the Bold & Gold website.


The results of a study by Hood, Chopra, and Wanielista provided promising results for the use of Bold & Gold for phosphorus removal. In field scale testing, Bold & Gold had a 71% removal efficiency of total phosphorus. This was compared to sandy soil which had many negative values, indicating significant leaching of total phosphorus from the sod. The average Soluble Reactive Phosphorus (phosphorus that is readily available to plants and algae) removal efficiency was 95%. Overall, the Bold & Gold system performed much better when compared to a sandy soil bio-filtrationThe technique of removing pollutants from runoff as it infiltrates through the soil. system. [2]

External links

Application in an exfiltration trench: [ downward movement of water through the soil, the downward flow of runoff from the bottom of an infiltration BMP into the soil.Loss of water from a drainage system as a result of percolation or absorption into the surrounding medium (e.g., the infiltration of water into the native soil through a perforated pipe wall as it is conveyed).%20Trench.pdf]

  1. Stormwater Treatment Environments, LLC. Success Stories. Accessed September 8, 2017.
  2. Hood A, Chopra M, Wanielista M. Assessment of Biosorption Activated Media under Roadside Swales for the Removal of Phosphorus from Stormwater. Water. 2013;5:53-66. doi: 10.3390/w5010053.