What Causes Sulfur and Methane Gases in Water, and How Are They Removed?

Sulfur gas (hydrogen sulfide) can form as organic material breaks down without oxygen or through the activity of sulfur-reducing bacteria. It produces the familiar rotten-egg smell.

Methane may occur naturally in groundwater or enter a well because of certain nearby human activities. Unlike hydrogen sulfide, methane is colorless, tasteless, and odorless unless another gas is present with it.

These gases require different safety and treatment considerations. Hydrogen sulfide may be treated through oxidation, aeration, and filtration. Dissolved methane is generally removed by an aeration or degassing system that safely vents the gas outdoors. Because methane is combustible.