Method and system for the treatment of water and fluids with chlorine dioxide

A method for treating an aqueous fluid, the method comprising

• (i) directly introducing a chlorine oxide into an aqueous fluid to make a chlorine oxide containing aqueous fluid, wherein the chlorine oxide is generated chlorine dioxide, chlorite, or a combination thereof, and wherein the amount of chlorine oxide that is introduced into the aqueous fluid is a substoichiometric amount that provides a total dose of chlorine oxide that is less than a predetermined demand of the aqueous fluid for said chlorine oxide;
• (ii) circulating at least a portion of the chlorine oxide containing aqueous fluid such that chlorine oxide containing aqueous fluid flows as a continuously circulating fluid through a treatment system including a storage vessel and a venturi;
• and
• (iii) introducing a non-ozonated oxidant into the circulating fluid using the venturi, wherein said oxidant is air, oxygen (O2) or O2-enriched air,
• thereby forming an aqueous fluid containing a combination of the chlorine oxide and the oxidant.