Corrosion in manholes is primarily caused by what gas?

Hydrogen sulfide gas is a significant contributor to corrosion in manholes, primarily due to its highly corrosive nature when released in wastewater systems. This gas can originate from the anaerobic decomposition of organic materials in sewage, especially in areas with lower oxygen levels. Hydrogen sulfide can react with moisture and other elements to form sulfuric acid, which further accelerates the deterioration of concrete and metal structures found in manholes.

When exposed to this environment over time, manhole materials can degrade, leading to structural failures and increased maintenance costs. Understanding the role of hydrogen sulfide in corrosion is crucial for managing wastewater systems effectively, as it highlights the importance of monitoring gas levels and implementing corrosion control measures to protect infrastructure.