Summary of pollutant removal mechanisms
Summary of attenuation-removal mechanisms for primary pollutants found in stormwater runoff. (Adapted from Horner, 1994 as reported in the [ http://dnr.wi.gov/topic/stormwater/manual.html Wisconsin Storm Water Manual] Part 2 (n.y.)
Link to this table
| Mechanism | Pollutants affected | Promoted by |
|---|---|---|
| Sedimentation | Solids, BOD, pathogens, particulate COD, P, N, metals, synthetic organics | Low turbulence |
| Filtration | Solids, BOD, pathogens, particulate COD, P, N, metals, synthetic organics | Fine, dense herbaceous plants, constructed filters |
| Soil incorporation | All | Medium-fine texture |
| Precipitation | Dissolved P, metals | High alkalinity |
| Sorption - adsorption | Dissolved P, metals, synthetic organics | High soil Al, Fe, high soil organics (Met), circumneutral pH |
| Sorption - ion exchange | Dissolved metals | High soil cation exchange capacity |
| Oxidation | COD, petroleum hydrocarbons, synthetic organics | Aerobic conditions |
| Degradation - photolysis | COD, petroleum hydrocarbons, synthetic organics | Direct sunlight |
| Degradation - volatilization | Volatile petroleum hydrocarbons, synthetic organics | High temperature and air movement |
| Degradation - biological | BOD, COD, petroleum hydrocarbons, synthetic organics | High temperature and air movement |
| Plant metabolism | P, N, metals | High plant surface area |
| Pathogen die off | Pathogens | Plant excretions |
| Nitrification | Ammonia | Dissolved oxygen >2 mg/L, low toxicants, temperature >5-7°C, circumneutral pH |
| Denitrification | Nitrate, nitrite | Anaerobic, low toxicants, temperature >15°C |