Table 3

Process	Reaction	Redox potential (E_h in mV)
Aerobic:	O₂ + 4e⁻ + 4H⁺ → 2H₂O	600 ~ 400
Anaerobic:
Denitrification	2NO₃⁻+ 10e⁻ + 12H⁺→ N₂+ 6H₂O	500 ~ 200
Manganese IV reduction	MnO₂ + 2e⁻ + 4H⁺ → Mn²⁺ + 2H₂O	400 ~ 200
Iron III reduction	Fe(OH)₃+ e⁻ + 3H⁺ → Fe²⁺ + 3H₂O	300 ~ 100
Sulfate reduction	SO₄²⁻+ 8e⁻ +10H⁺ → H₂S + 4H₂O	0 ~ −150
Fermentation	2CH₂O → CO₂ + CH₄	−150 ~ −220

Source: Wikipedia, the free encyclopedia [6]
Table 3: The decreasing biological breakdown rate as function of the redox potential.