The Odor Control systems pull air from the room or tanks. This creates a slight negative pressure in the room or tanks, keeping air from releasing to the atmosphere. The air is pulled through a tower packed with plastic rock-like media. A recycle solution is pumped to the top of the tower, which then flows downward through the media like a waterfall to wash the gasses that pass upward. Chlorine and a caustic solution are added to the recycled flow to remove the unwanted gasses, including hydrogen sulfide.