RAS represents the "blue revolution." Because it uses so little water and occupies a small footprint, it can be placed anywhere. This reduces the carbon footprint of "food miles" by growing Atlantic Salmon in the Midwest or Tilapia in the city center. It protects wild oceans from pollution and prevents farmed fish from escaping into the wild.

In a RAS facility, the journey begins in the rearing tank. Here, fish live in high densities, eating and producing waste. In an open system, this waste would flow out into the environment. In RAS, the water is on a constant treadmill. It leaves the tank carrying uneaten food and metabolic byproducts, beginning its transformation back into life-sustaining liquid. The Filtration Gauntlet

The water first hits mechanical filtration, usually a rotating drum filter. This acts like a giant sieve, catching solid particles before they can break down. Once the "heavy" trash is removed, the water moves to the most critical stage: the biofilter.

After the biofilter, the water is "polished." It passes through degassers to strip out carbon dioxide and UV sterilizers or ozone generators to kill any lurking pathogens. Finally, pure oxygen is injected, bringing the levels far higher than what nature could provide.