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] | No | |
| Phosphorus retention | No to slight [4] | No [5] | No | No | |
| Handling concerns | Potential explosive concerns in closed space situations; volatile compounds (depending on pyrolysis temperature) [6] | Dust [7] | None | None | |
| Soil hydraulic properties | Significant improvement [8] | Significant improvement [9] | Significant improvement [10] | Improvement if incorporated [11] | |
| Soil physical properties | Significant improvement [12] | Moderate improvement [13] | Significant improvement [14] | Improvement if incorporated [15] | |
| Plant/microbial effects | Beneficial but varies with feedstock [16] | Beneficial [17] | Beneficial if not fresh [18]; [19] | Beneficial for fungi | |
| Availability | Multiple distributors [20] | Widely available [21] | Widely available | Widely available | |
| Specifications/standards available | Limited due to variability with feedstocks [22] | Yes [23] | Yes [24] | Yes for chips used for energy production [25] | |
| 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 | Extensive needs since there are limited studies in stormwater applications. | |
| Applications | [26] | [27] | [28] | [29] | |
| Chemical properties | [30] | [31] | [32] | [33] | |
| Sustainability | Sustainable, but has current market constraints [34] | Sustainable [35] | Sustainable | Sustainable | |
| Potential contaminants | Minor risk - metals and polycyclic aromatic hydrocarbons (PAHs) [36] | Low risk - possible chloride depending on preparation method [37] | Low risk; avoid CCA and creosote-treated sources [38] | ||
| Test methods | Not standardized but International Biochar Initiative widely used [39] | Not standardized but multiple methods available [40] | [41]; [42] | [43] | |
| Effects of aging/Life expectancy | Varies with production method [44] | Decomposes slowly unless nutrients are added [45] | Ages relatively rapidly; aging generally benefits stormwater function by reducing nutrient loss and reducing microbial competition for nutrients [46] | Slow to moderate depending on source and application conditions [47] | |
| Notes | Characteristics vary with feedstock and pyrolysis temperature | Coir must be composted or incorporated with compost, lime, fertilizer, and/or microbes |