Water that is giving off an unmistakable smell is most likely contaminated with hydrogen sulfide. Hydrogen sulfide does not typically present health problems at the levels it is found in domestic drinking supplies. In any case, it is an inconvenience — especially to one’s nose, as it creates a “rotten egg” smell. So removal of h2s from water is important. H2S removal from water sources is a need for wastewater treatment plants to secure the health of infrastructure and users.