Bacterial anaerobic corrosion

Bacterial anaerobic corrosion is an indirectly induced by bacterial oxidation of metals.

In a moist environment found under anoxic conditions, corrosion of metals as a result of removing a protective layer of elemental, molecular hydrogen by bacteria instead of ( hydrogen corrosion), for example, in the bottom of iron pipes water pipes, of steel sheet piles in oil tanks and sinks of diesel injection systems.

" Ignoble " metals reacted, eg iron ( Fe), go into contact with water as the positively charged metal ions ( eg Fe2 ) in solution, with the freed up negative charges are hydrogen ions ( H ) to elemental, molecular hydrogen (H2):

Usually, the resulting elemental hydrogen creates the metal to form a thin film, thus protecting it from further resolution. However, if (soluble ) sulfates and sulfate - reducing bacteria ( Sulfate, eg Desulfovibrio ) exists, then an oxidation of the hydrogen to form water (H2O) and hydrogen sulfide ion (HS -) are reduction of sulfate:

The iron ions are precipitated mostly with the hydrogen sulfide as an iron (II ) sulfide, partly reacted with water and an iron (II) hydroxide (Fe (OH ) 2) precipitation:

The blackening by the black iron (II ) sulfide suggests this type of corrosion, namely with bacterial sulfate reduction, down.

In sum, results in the following overall equation:

The resulting damage this way can be considerable.