<p>A method and a system for supplying a carbon dioxide fluid feed from a carbon dioxide purifying means to one or more applications. The feed is combined with contaminants at the applications to form an effluent, and at least one effluent is returned to the purifying means for recycling the carbon dioxide. Carbon dioxide from a carbon dioxide source is combined with the carbon dioxide of the system so that the purity of the carbon dioxide from the source is upgraded prior to the applications.</p>