AWWA ACE63013

Research has shown that higher levels of copper appear in drinking water conveyed throughrelatively new copper piping systems; older piping systems typically deliver lower copperlevels in their drinking water. This research contributes field data from a real drinkingwater distribution system, providing a better understanding of this phenomenon, as itrelates to treatment considerations and compliance with the Lead and Copper Rule.Copper pipes and copper levels were sampled from drinking water taps of 16 buildingswith pipes ranging in age from less than 1 to 48 years. Water samples from each buildingwere collected before and following a 16-hour stagnation period. A piece of domesticcold water pipe was cut from each building near the tap where the water samples wereobtained and analyzed to determine the mineralogy of the copper scale present using xraydiffraction (XRD) and x-ray photoelectron spectroscopy (XPS) technologies.The samples showed remarkable variation in scale appearance and mineralogy,demonstrating the diversity of pipe scales present within a single distribution system. Amix of highly soluble and relatively insoluble copper phases were identified in the realworld scale. Both stable scales, such as malachite, and relatively instable solids, such ascupric hydroxide appear in pipes irrespective of age. In many samples cupric hydroxideand cuprite appeared on the surface of the scale while malachite was in the bulk. Coppercyanide was also identified in two pipe scales. XPS and XRD are shown to becomplimentary techniques for characterizing complex scales made up of a mixture ofamorphous and crystalline solids Includes 10 references, table, figures.

Product Details

Edition:

Vol. - No.

Published:

06/01/2006

Number of Pages:

8

File Size:

1 file