Which sludge gas encountered at sewage treatment plants is corrosive and damaging to metals?

Hydrogen sulfide is a colorless gas with a characteristic foul odor of rotten eggs, which is a byproduct of the decomposition of organic materials in sewage. It is known for its corrosive properties, particularly when it comes in contact with metals. This corrosiveness can lead to significant damage in sewage treatment facilities, affecting infrastructure, equipment, and piping. The presence of hydrogen sulfide in sewage can create challenges in the maintenance and safety of the plant, necessitating protective measures and materials specifically designed to withstand its effects.

In contrast, carbon dioxide, ethane, and nitrogen do not have the same corrosive properties as hydrogen sulfide. Carbon dioxide, although it can potentially affect the pH level in wastewater treatment, does not exhibit the same degree of metal corrosion. Ethane is a hydrocarbon gas that may be present but does not pose a corrosive threat to metals. Nitrogen, being an inert gas in most of its forms, does not corrode metals either. Therefore, hydrogen sulfide stands out as the gas that can cause significant damage to metals in sewage treatment settings.