Nutrient Stimulation of Sulfolane Biodegradation in a Contaminated Soil from a Sour Natural Gas Plant and in a Pristine Soil

Abstract

Natural gas in western Canada can contain up to 35% H2S. The Sulfinol® process for sour gas treatment makes use of sulfolane and an amine to remove H2S and other sour components from natural gas. Sulfolane has leached into groundwaters at sour gas treatment plant sites, and poses a risk for off-site contamination. Sulfolane biodegradation was monitored in shake-flask cultures and air-sparged microcosms inoculated with uncontaminated topsoil or with sulfolane-contaminated soil obtained near a Sulfinol process building at a sour gas treatment facility in western Canada. For both soils, supplementation with a source of fixed nitrogen stimulated sulfolane biodegradation. Topsoil cultures and microcosms were only slightly affected by the addition of phosphate. Contaminated soil microcosms and cultures were stimulated by phosphate addition, but not to the same degree as by the addition of nitrogen. For these cultures and microcosms, amendment with both fixed nitrogen and phosphate produced an additive effect. It was possible to predict the nutrient requirements of air-sparged microcosms inoculated with each soil type using shake-flask cultures. Shake-flask cultures require less time and effort and fewer materials than the more complex air-sparged soil microcosms, and will be useful for large-scale experiments to predict the nutrient supplements required for bioremediation of sulfolane-contaminated sites.