Corrosion in sewer pipes happens primarily due to hydrogen sulfide gas and can usually be found in concrete or metal pipes. Hydrogen sulfide is not just responsible for corrosion; it is also the cause of the offensive stench that emanates from sewer lines. The gas is also highly poisonous and flammable. Pipes damaged by corrosion can eventually be destroyed and can cause environmental pollution and serious accidents. With the advent of trenchless rehabilitation methods, methods like spot repair, grouting, relining, pipe bursting, sliplining etc. are used to repair pipes damaged by corrosion. Newer materials like liners impregnated with resin, HDPE pipes, and PVC pipes are resistant to corrosion, have good durability and last longer.
Trenchlesspedia Explains Corrosion
Sewage water carries biological matter that produces microbes that live beneath the water line. This bacterium converts the sulfate present in the water to ionic sulfide, which is then chemically transformed into hydrogen sulfide. As sewage water is disturbed by turbulence, the gas is released into the surrounding air. Another set of bacteria that reside above the water line, known as Thiobacillus again converts the hydrogen sulfide into sulfuric acid which falls back into the waste water where it turns back into sulfate. This process repeats itself endlessly. To prevent corrosion, some methods like regular cleaning of debris to prevent accumulation of slime, chemical addition to control dissolved sulfide, turbulence reduction by ensuring flow control, and using corrosion resistant coatings for the internal surface can be used. Replacing old pipes with corrosion resistant pipes is the best way to counter corrosion related issues.