Sewage Pipe

Definition - What does Sewage Pipe mean?

A sewage pipe is a pipe used to transport wastewater or sewage from homes and industries, i.e. it is a pipe for carrying off water or sewage. Sewage pipes are affected by corrosion that reduces the longevity of the pipes and breaks down the sewage network.

A sewer network consists of many pipes, and one hopes that it will last for many years. But increased urban pressure causes high concentrations of sewage that produces corrosive acid, which ultimately corrodes these pipes more quickly.

Corrosionpedia explains Sewage Pipe

In the piping network, sewage pipes behave differently in different corrosion environments. Most sewage pipes are made out of cast iron and are normally heavy. Cast iron pipes are highly vulnerable to moisture condensation and acidic gases. They can show a single penetration failure because of internal stresses. Sewage is a liquid-carried waste, in solution or suspension.

The presence of hydrogen sulfide gas in the sewer is the primary cause of this pipe corrosion. This hydrogen sulfide produced from sulfates is found in both raw water sources and in water treatment plants. All the accumulated sulfates turn into sulfide in low-oxygen environments, and finally form corrosive sulfuric acid through bacterial action, which causes corrosion in the crown of the pipe. This corrosion is also known as "crown corrosion". When sewage pipe material comes into contact with sulfuric acid, the pipe material corrodes, ultimately causing failure.

Bacteria corrode sewer pipes from the inside. The bacteria from the genera Acidiphilium and Mycobacterium are found to be culprits. The genre grows in high acidity, where they oxidize sulfur compounds into sulfuric acid.

To avoid sewage piping corrosion, the following can be considered:

  • Use inert materials pipes
  • Use sacrificial lining in pipes
  • Use acceptable linings, e.g. cement mortar lining, either with sulfate resistance or high alumina cement in metallic pipes
  • Good ventilation to remove moisture condensation
  • Periodic flushing of sewers

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