An atmospheric recycling manifold was a technology utilized aboard 22nd century Starfleet vessels, for the purpose of routing the transfer lines of the ship's central ventilation system to the appropriate tanks. The manifold included a control panel consisting of six green lights with corresponding switches which controlled the feed. The switches could be recalibrated in sequence for whichever gas was to be released into central ventilation.
In 2152, when a series of non-corporeal beings called "Wisps" began taking control of the crew of the Enterprise NX-01, Captain Archer and Sub-Commander T'Pol instructed Doctor Phlox as to how to recalibrate the manifold in order to release carbon dioxide throughout the ship, thereby rendering the affected crew unconscious and evicting the Wisps from their bodies. After rerouting the transfer lines to the carbon dioxide tanks, Phlox was required to purge the osmotic filters, successfully releasing the gas. (ENT: "The Crossing")