Chlorination and aeration can remove sulfuric gas and odors from well water. The strong, rotten egg odor occurs when bacteria convert elemental sulfur into hydrogen sulfide gas.
In the chlorine bleach removal method, the bleach reacts with hydrogen sulfide dissolved in the water to produce an insoluble form of sulfur. The system includes a 500- to 1,000-gallon storage tank that provides a place for the solid sulfur to settle out of the water. An alternative is to use a filter to remove the particulate matter after the bleach reaction. If removal requires adding large amounts of chlorine to the water, the owner must sometimes install a dechlorinator to remove any excess from water used for drinking or cooking.
Aeration removes some of the odor-causing gas. It also removes some iron. The process requires a special aeration tank, and the sulfur odor remains strong around the tank and may still be present in the water. The process is much more effective with an activated carbon filter system.
If the rotten egg smell only occurs in the hot water supply, a simple solution is to remove the magnesium rod from the water heater. Manufacturers install this rod to reduce corrosion in the tank, but it serves as a catalyst in converting sulfur to sulfur dioxide. Unfortunately, removing the rod usually voids the manufacturer's warranty. Replacing it with an aluminum rod continues to provide corrosion protection for the unit.