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Control of new copper corrosion in high‐alkalinity drinking water
Author(s) -
Grace Stephen,
Lytle Darren A.,
Goltz Mark N.
Publication year - 2012
Publication title -
journal ‐ american water works association
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.466
H-Index - 74
eISSN - 1551-8833
pISSN - 0003-150X
DOI - 10.5942/jawwa.2012.104.0002
Subject(s) - alkalinity , copper , chlorine , chemistry , environmental chemistry , environmental science , calcium carbonate , water treatment , environmental engineering , metallurgy , materials science , organic chemistry
Research and field experience have shown that high‐alkalinity waters can be associated with elevated copper levels in drinking water. The objective of this study was to document the application of orthophosphate to the distribution system of a building with a copper problem associated with high‐alkalinity source water. The alkalinity and pH of the water were 273 mg/L calcium carbonate and 7.4, respectively, and copper levels at taps ranged from 1.4 to 2.4 mg/L. Experimental bench‐scale jar tests proved to be useful for establishing an appropriate orthophosphate (PO4) dose. A simple chemical feed system delivered orthophosphate to the building at a dose of approximately 3 mg/L PO4. Within several weeks, copper levels throughout the building dropped below the Lead and Copper Rule copper action level of 1.3 mg/L. Orthophosphate levels remained consistent across the building and did not change during stagnation. The addition of orthophosphate also increased chlorine residuals of flushed water samples.