Engineered (bioretention) media amendments material properties and specifications
Engineered (bioretention) media amendments material properties and specifications.
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| Property | Al- and Fe-water treatment residuals | Ca-water treatment residuals1 | Iron | Expanded lime | Expanded aluminum | Taconite |
|---|---|---|---|---|---|---|
| Phosphorus leaching | No | No | ||||
| Phosphorus retention | Yes | Yes | ||||
| Handling concerns | Dust may be corrosive and irritant to skin and eyes [1] | |||||
| Soil hydraulic properties | Mixed results; has shown clogging when incorporated into soil | |||||
| Soil physical properties | Mixed results; may initially improve soil structure but over time may impair structure through formation of cementitious compounds | |||||
| Plant effects | Improves plant response in acid soils; may have adverse effects if pH becomes elevated [2] | |||||
| Availability | Depends on source; many materials are widely available as they have been treated as wastes and landfilled (e.g. spent lime) [3] | |||||
| Specifications available | No [4] | |||||
| Cost | Can be inexpensive if sources exist locally (e.g. spent lime from water treatment) | |||||
| Research needs | Performance in incorporated media; design specifications; maintenance requirements | |||||
| Applications | [5] | |||||
| Chemical and physical properties | [6] | |||||
| Sustainability | Sustainable | |||||
| Potential contaminants | Elevated pH; avoid waste products that may have elevated concentrations of metals (e.g. spent lime from wastewater treatment) | |||||
| Test methods | Standard test methods not available; methods may be described in individual reports [7] | |||||
| Effects of aging | Not expected to be a concern [8] | |||||
| Notes |
1Includes spent lime