Corrosion in sewer system occurs due to production of

Explanation:

Corrosion of sewers due to biological reaction:

• Corrosion in sewer pipes happens primarily due to hydrogen sulfide gas

• H2S in sewer is usually produced by bacteriological reduction of sulphates.
• In the presence of air, H2S gets oxidized to H2SO4 and this sulphuric acid reacts with cement constituents of concrete.

Factor responsible for sewer corrosion:

• Sewers with low velocities ( insufficient self-cleansing) encourage the growth of anaerobic bacteria in a slime layer.
• Improper composition of sewer material ( like non use of sulphate resistant elements ).
• Due to high BOD.
• Due to high temperature.
• Improper maintenance of sewer.
• Improper ventilation.