Bold & Gold

What is it?

Bold & Gold Filtration Media (Ferguson Waterworks, 2025)

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 stormwater, wastewater and agricultural applications such as retention basins, swales and rain gardens, urban gardens and soil cells, permeable pavements, green roofs, filter strips and more. Bold & Gold is composed of a patented blend of mineral materials, sand, and clay.

How is it being used?

• Bold & Gold was used to remove total phosphorus in an urban on-line up-flow filter and an off-line filter in Florida (FDOT, 2014).
• It was also used in Florida in residential swales covered with native soil and sod to remove nitrogen and phosphorus from stormwater (FDOT, 2023).
• No projects that used Bold & Gold were found in Ontario.

Detailed drawings and product specifications are available here.

Benefits

The results of a study by Hood, Chopra, and Wanielista (2013) 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-filtration system .

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The technique of removing pollutants from runoff as it infiltrates through the soil.

Surface runoff from at-grade surfaces, resulting from rain or snowmelt events.

Ground depression acting as a flow control and water treatment structure, that is normally dry.

Mineral 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.

1. 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).

The natural ground material characteristic of or existing by virtue of geographic origin.

The technique of removing pollutants from runoff as it infiltrates through the soil.

A shallow constructed channel, often grass-lined, which is used as an alternative to curb and channel, or as a pretreatment to other measures. Swales are generally characterized by a broad top width to depth ratio and gentle grades.

Surface runoff from at-grade surfaces, resulting from rain or snowmelt events.