A new scrubber at a Camden, NJ bio solids processing facility uses advanced technology to cut the cost of odor control. The system was designed, built and installed by Bay Products with process design assistance from Lantec Products. A single tower is used to remove malodorous gases from air in two stages having separate sumps for the recirculated scrubbing solutions. The lower stage absorbs ammonia using sulfuric acid to neutralize it. The air then passes up the tower into second stage where hydrogen sulfide is neutralized with caustic soda and converted to harmless sulfate by a hypochlorite bleach solution. A mist eliminator and a sealed collector tray between stages prevent mixing of the two liquids, while allowing air to pass. Odor-free air exits the stack to atmosphere.