AWWA WQTC62369

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 Cl₂) was slightly increased by cupric. In copper pipes, which havea virtually unlimited supply of metallic copper (Cu⁰) 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 Cu¹⁺ formed by reaction between Cu⁺² and Cu⁰. Includes 16 references, table, figures.

Product Details

Edition:

Vol. - No.

Published:

11/01/2005

Number of Pages:

12

File Size:

1 file , 750 KB