Table 4.

Key processes adopted in the treatment of polluted stormwater [184]

Pollutant in stormwater	Key processes
Sediment	Physical filtration is done by filter media Settlement during ponding
Nitrogen	Nitrification and denitrification Decomposition Adsorption Biotic assimilation by plants and microbes Physical filtration of sediment-bound fraction
Phosphorous	Decomposition Adsorption Biotic assimilation by plants and microbes Physical filtration of sediment-bound fraction
Heavy metals	Oxidation and reduction reactions Biotic assimilation by plants and microbes Physical filtration of sediment-bound fraction
Pathogens	Adsorption and desorption Physical filtration by filter media Natural or predation die-off
Organic micropollutants	Adsorption Biodegradation