Case History: Odor Reduction In Wastewater Collection Wetwell

A southern municipal POTW had difficulties controlling emission odors from its collection wetwell located close to a recreational marina. The system was equipped with a two-stage air scrubber. Both the first and second stage towerswere 36" diameter with a packing height of 10' using 2" packing balls. Water was circulated at a rate of 50gpm and was held in a 36" sump. The scrubber had an airflow rate of 2000scfm. Caustic soda was used to react and trap the hydrogen sulfide (H₂S) gas in the air stream going to the scrubber from the covered wetwell. Although the caustic treatment reduced the incoming H₂S from a range of 50- 90ppm down to 4ppm, the operation was difficult to control. Handling the caustic was not operator friendly and odor complaints continued from the neighbors. Q² Technologies was asked to provide a better program solution.