The City of Escondido owns and operates the Hale Avenue Resource Recovery Facility (HARRF) located at 201 North Broadway in Escondido, California. HARRF receives and treats wastewater from residential, commercial and industrial properties in Escondido. An odor control system consisting of a bioscrubber and mist scrubbers treats 66,000 cubic feet per minute of foul air from the primary clarifier building. Increased odors at the plant and complaints from nearby residents led to a study of the bioscrubber. Data from sampling indicated that use of sulfide-laden primary effluent as a wetting agent may be responsible for the odors. The study evaluated short term and long term improvements to the odor control system and other plant facilities, and provided a preliminary cost estimate for implementing recommended improvements.