Advancing Odor Control to New Levels

In October 1999, an odor control system was brought on-line at the Gurnee Sewage Treatment Plant to treat foul air from its solids handling facilities. However, even with the new system, the district continued to receive many odor complaints from its neighbors. So the district completed extensive testing to better define the problem. Following optimization, the two-stage system achieved 90% removal of reduced-sulfur compounds and 99% removal of hydrogen sulfide. The performance equaled the best available liquid scrubber technology at the time, but neighborhood complaints continued. Based on an analysis of scrubber operating data and observations of the scrubber plume, it was determined that to reduce offsite odors, the scrubber would have to remove an additional 90% to 99% of organic reduced-sulfur compounds - without adding any residual odor from the scrubbing solution chemicals. By applying recent advances in packing media and extending the liquid scrubbing solution's residence time in the tower system to Gurnee's packed towers, it was believed that a higher performance level would be achieved.