Case Study

The Situation

The Orange County Sanitation District (OCSD) approached its Odor Control Master Plan (OCMP) from a unique and innovative perspective. In lieu of the traditional focus on hydrogen sulfide (H₂S) and general odor, OCSD conducted a wide sweep of sampling and analysis of all plant process areas to determine the top offenders at its two coastal Southern California plants. Key odorants were identified using chemical and sensory analytical methods, and using the Weber-Fechner relationship between each odorant concentration and their perceived intensity, maximum fenceline concentrations below nuisance were determined.

The Test

A comprehensive evaluation of foul air management technologies was conducted including a bibliographic search of all viable vapor phase odor control technologies followed by in-situ technology testing. Test data would be used for supporting the selection of targeted foul air treatment at specific sources and for facilitating Capital Improvement Plan decisions.

Pilot testing was conducted at trunk line scrubbers at the Huntington Beach plant for the following technologies:

• Biotower with reticulated polyurethane foam cubes
• Biotower with Matala® filter media mat and foam filter media mat
• Biofilter with engineered media (Enhanced Cell-Max™)
• Biofilter with bioshell media
• Biofilter with lava rock media (Crater-Max®)
• High capacity carbon media
• Coconut shell carbon media
• Combination coconut shell carbon media + potassium permanganate impregnated activated carbon

The Results

Where high H₂S and/or MM removal is required, biological technology mitigation measures were determined to generally provide the best fit. Enhanced Cell-Max™ operated at 45 seconds EBGRT outperformed biotrickling filter and bioscrubber technologies with greater than 99.5 percent removal of H₂S and approximately 99 percent removal of MM.