The world's infrastructure is aging. Corrosion is the major cause of this problem.
Metallic pipes can corrode when placed in poorly aerated, poorly drained soils of low resistivity.
The presence of sulfate-reducing bacteria will accelerate this corrosion. Internally, unprotected concrete sewer pipes are rapidly deteriorated by the presence of sulfuric acid in a sanitary sewer system, which is generated through the hydrogen sulfide cycle.