Nitrate Accumulation and Removal
through Sulfur Denitrification in
Georgia Aquarium’s Ocean Voyager
Georgia Aquarium’s Ocean Voyager is a 6.3 million gallon recirculating saltwater exhibit housing whale sharks and manta rays, among many other species. The system has been in continuous operation for over ten years, during which there has been a significant nitrate accumulation. Although sulfur denitrification was part of the original exhibit design, the reactors had a variety of challenges which ultimately prevented them from being effective. Water changes were also ineffective due to cost and logistical restrictions. In early 2015, the original OV denitrification system was completely dismantled and rebuilt using a new design influenced by years of trials and experimentation. Key elements include careful reactor size determination, vertical vessels with recirculating flow, and aragonite in the sulfur chambers. During two years of operation, the OV sulfur denitrification system has dropped nitrate levels from approximately 180mg/L NO3-N to under 60mg/L.