Engineered (bioretention) media organic material properties and specifications
Engineered (bioretention) media organic material properties and specifications.
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| Property | Biochar | Coir | Compost | Peat | Wood chips |
|---|---|---|---|---|---|
| Phosphorus leaching | No [1] | No to slight [2] | Yes [3] | ||
| Phosphorus retention | No to slight [4] | No [5] | No | ||
| Handling concerns | Potential explosive concerns in closed space situations; volatile compounds (depending on pyrolysis temperature) [6] | Dust [7] | None | ||
| Soil hydraulic properties | Significant improvement [8] | Significant improvement [9] | Significant improvement [10] | ||
| Soil physical properties | Significant improvement [11] | Moderate improvement [12] | Significant improvement [13] | ||
| Plant/microbial effects | Beneficial but varies with feedstock [14] | Beneficial [15] | Beneficial if not fresh [16]; [17] | ||
| Availability | Multiple distributors [18] | Widely available [19] | Widely available | ||
| Specifications/standards available | Limited due to variability with feedstocks [20] | Yes [21] | Yes [22] | ||
| Cost | |||||
| Research needs | Feedstocks suitable for stormwater applications | Phosphorus fate in stormwater applications | Identifying compost-containing media mixes that do not leach phosphorus but provide other benefits | ||
| Applications | [23] | [24] | [25] | ||
| Chemical properties | [26] | [27] | [28] | ||
| Sustainability | Sustainable, but has current market constraints [29] | Sustainable [30] | Sustainable | ||
| Potential contaminants | Minor risk - metals and polycyclic aromatic hydrocarbons (PAHs) [31] | Low risk - possible chloride depending on preparation method [32] | |||
| Test methods | Not standardized but International Biochar Initiative widely used [33] | Not standardized but multiple methods available [34] | [35]; [36] | ||
| Effects of aging/Life expectancy | Varies with production method [37] | Decomposes slowly unless nutrients are added [38] | Ages relatively rapidly; aging generally benefits stormwater function by reducing nutrient loss and reducing microbial competition for nutrients [39] | ||
| Notes | Characteristics vary with feedstock and pyrolysis temperature | Coir must be composted or incorporated with compost, lime, fertilizer, and/or microbes |