Liquid Phase Collection System Sulfide Control--Early Field Results using a New Low-Hazard Iron Product

Iron salts (ferrous/ferric chloride and sulfate) have been used for over 70 years in hydrogen sulfide odor control applications and are a well understood technology with a proven track-record of successful long-duration H2S control in collection systems, solids processing units, solids transfer lines and anaerobic digesters. While iron salts are an inexpensive solution, the hazardous nature of the chemical constrains their use outside the treatment plant. Many municipalities are wary of bringing hazardous chemicals to smaller pump and lift stations in residential neighborhoods. Chemicals with lower hazard levels, such as magnesium hydroxide and especially calcium nitrate (CaN), are thus the odor control technology of choice for many such applications across the country. Through widespread use, CaN is well-known as an simple and effective odor control solution for medium to long-duration lines in the collection system, and can be used in applications to remove sulfide that is already present at its point of addition (curative) or before the sulfide appears to prevent its formation (preventative). Nevertheless, certain drawbacks have been largely disregarded for lack of better options.