Control of Hydrogen Sulfide from Groundwater Using Packed-Bed Anion Exchange and Other Technologies

Hydrogen sulfide imparts odors and taste to drinking water and can be corrosive to distribution systems. Groundwater sources used to produce drinking water tend to have sulfide concentrations ranging from below 0.1 to over 3 mg/L. Under anaerobic conditions, hydrogen sulfide can be formed from reduction of sulfate and elemental sulfur through chemical or biological reactions. Therefore, to decrease the potential for hydrogen sulfide in water systems, control of all forms of sulfur should be consistent. Hydrogen sulfide in groundwater can be controlled through conversion or removal mechanisms. Conversion reactions result from chemical or biological reactions that oxidize hydrogen sulfide to elemental sulfur or sulfate, depending on the reaction conditions. Removal reactions include stripping, anion exchange, or formation of a precipitate that can be removed through solid/liquid separation processes. In many groundwater treatment systems, hydrogen sulfide is controlled through aeration, chlorine oxidation, or a combination of these two methods. In addition to chlorine, other oxidizers can be used including hydrogen peroxide, UV, ozone, or potassium permanganate. The main factors that influence whether hydrogen sulfide is oxidized to elemental sulfur and/ or sulfate are pH, temperature, and the type and dose of oxidant. In recent years alternative treatments technologies such as anion exchange, have become available. It is interesting to note that this technology was proposed as early as the middle of last century. Although large scale anion exchange has not been implemented, its application for the removal of hydrogen sulfide is feasible based on anion exchange principles. This research was designed to evaluate feasible options for controlling hydrogen sulfide from groundwater sources. The feasibility of using anion exchange was investigated through pilot-scale testing of four groundwater sources. In addition, the performance of typical and alternative chemical oxidizers to control hydrogen sulfide was evaluated