Iron – The Optimal Solution for Odor and Corrosion

The City of Dallas collection system services approximately 1.4 million people with an average daily flow of 160 mgd. Traditionally, hydrogen sulfide, also known as sewer gas, had been emitted from various locations in the collection system, resulting in as many as 50 complaints per month from multiple locations in the city. Odors were an underlying indicator of a greater potential issue: corrosion of sewer mains throughout the collection system and the capital repair costs associated with replacement. The City of Dallas evaluated various options to eliminate the odor problems, and eventually selected iron salts, specifically ferrous sulfate, to eliminate the problem.Multiple ferrous sulfate feed sites were set up at strategic locations, taking into account collection system flows, complaints, lift stations, and facility locations. A continual testing and monitoring program was also established to ensure system control and maintenance.