When held stagnant in relatively new copper pipes, chloramine and free chlorinedisinfectants decay rapidly. In the presence of soluble and insoluble cupric, species, freechlorine decay is most rapid in the presence of cupric hydroxide solid surfaces, whereaschloramine decay (as Clsub2/sub) was slightly increased by cupric. In copper pipes, which havea virtually unlimited supply of metallic copper (Cusup0/sup) while in service, chloramine andfree chlorine decayed almost completely during overnight stagnation even after monthsof exposure. The rate of this reaction was unaffected by extra ammonia, but it wasslowed by the addition of phosphate or aluminum which presumably formed barriersbetween the water and reactive surface sites on the pipe. Experimental results areconsistent with a chloramine decay path via Cusup1+/sup formed by reaction between Cusup+2/sup and Cusup0/sup. Includes 16 references, table, figures.
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Edition: Vol. - No. Published: 11/01/2005 Number of Pages: 12 File Size: 1 file , 750 KB