Sioux City, Iowa Odor Control: A Multiphase Approach

This paper presents a summary of the multiphase approach and measures taken by the City of Sioux City, Iowa for controlling nuisance odors and providing a safe working environment for employees. Phase 1 involved the identification of sources and changes to the wastewater pretreatment program. Phase 2 involved the odor control program, in which US Peroxide, LLC was selected using the RFQ (Request for Qualifications) process. The results of the proof of concept phase of the odor control program are presented, which was conducted in May 2012. Chemical dosing with hydrogen peroxide (H2O2) and with peroxide regenerated iron sulfide control (PRI-SC®) technology was implemented within the collection system, dramatically reducing liquid and vapor phase sulfide levels. Compared with April 2012 baseline numbers, the May 2012 program results obtained percentage reductions in atmospheric H2S ranging from 77 – 91%. The number of odor complaints received by Sioux City from the community substantially decreased, and trended downward since the start of the PRI-SC® program. Phase 3 was the implementation of an Odor Control Ordinance, which set a framework by which odor complaints would be investigated and ramifications would be established. Phase 4 is the continuation of the program, in which the odor sources are monitored, the chemical dosing regimen is optimized, and progress is sustained.