A method for scavenging hydrogen sulfide from geothermal steam in a condenser under vacuum. A fine curtain of atomized acrolein-water droplets may be sprayed into geothermal steam condensers in an amount of approximately 2:1 molar ratio of acrolein to H2S based on hydrogen sulfide in the incoming steam from the turbine. The range being approximately 0.1 ppm to 500 ppm of sulfide. The acrolein is allowed to react with the gas phase H2S to form non-volatile aldehyde byproducts which partition into the water phase, are returned to the cooling tower and ultimately removed by normal cooling-tower blow down.