Source of Hydrogen Sulfide
Hydrogen Sulfide (H2S) is a gas which imparts its "rotten egg" odor to water supplies. Such waters are distasteful for drinking purposes and processes in practically all industries. Most sulfur waters contain from 1 to 5 ppm of hydrogen sulfide. Hydrogen sulfide can interfere with readings obtained from water samples. It turns hardness and pH tests gray, and makes iron tests inaccurate. Chlorine bleach should be added to eliminate the H2S odor; then the hardness, pH and iron tests can be done. Hydrogen sulfide can not be tested in a lab, it must be done in the field. Hydrogen sulfide is corrosive to plumbing fixtures even at low concentrations. H2S fumes will blacken or darken painted surfaces, giving them a "smoked" appearance.
Treatment of Hydrogen Sulfide
H2S requires chlorine to be fed in sufficient quantities to eliminate it, while leaving a residual in the water (3 ppm of chlorine is required for each ppm of hydrogen sulfide). Activated carbon filtration may then be installed to remove the excess chlorine.