Selection and full‐scale use of a chelated iron absorbent for odor control

Abstract

ABSTRACT: Odors had been a chronic operational problem at the City and County of Honolulu's Sand Island W W T P since it began service in 1979. A field survey identified the release of hydrogen sulfide as the major odor source and concluded that off‐gas collection and treatment afforded the best methods for abatement. A pilot program was initiated that tested caustic scrubbing and a chelated iron catalytic absorbent. The latter was selected based on performance, economics, and chemical‐handling requirements. The full‐scale system was designed to treat 10.9 m3/s (23 000 scfm) of air and achieve a 95% reduction in hydrogen sulfide levels, which were expected to range from an average of 75 ppm (V/V) to a peak of 150 ppm. The design used two fiberglass packed towers operating in series followed by activated carbon adsorbers. The system has been in service since June 1986 and has shown itself to be effective in controlling odors.