Abstract: An improved contaminant abatement process is disclosed which provides effective, cost efficient abatement of contaminants, and particularly hydrogen sulfide and sulfide ions, from geothermal power plant effluents. The process of the present invention is suitable for use with geothermal power plant effluent treatment systems having a primary hydrogen sulfide abatement system for removal of hydrogen sulfide from noncondensable gases, and a secondary hydrogen sulfide abatement system for removal of hydrogen sulfide from condensate. At least a portion of the condensate separated in the primary condenser is diverted for reinjection to the geothermal well prior to treatment in the secondary hydrogen sulfide abatement system. Diversion of at least a portion of the condensate comprising substantial amounts of hydrogen sulfide and sulfide ions reduces the cost of secondary hydrogen sulfide abatement, and reduces the costs involved in abatement of other contaminants.