This powerpoint presentation begins by providing background information on pitting corrosion of copper pipes. A case study is presented of a large water utility in Florida that experienced
widespread pitting corrosion in copper plumbing. Initially, the community started orthophosphate addition and
pH change to mitigate problem in 2003,
but switched to 50:50 ortho-polyphosphate blend in
September 2005. The objective was to determine how phosphate treatment
impacted the surface of copper pipes that were
removed from a real distribution system
that experienced localized corrosion. Analytical methods included: solids analysis;
Scanning Electron Microscopy;
morphological and phase contrast; Energy Dispersive Spectroscopy;
elemental composition;
X-ray Diffraction; and,
mineralogy. Results of orthophosphate impact indicated:
lack of detection one year into treatment;
below EDS detection;
carry-out issues;
dose consistency; and,
accumulation rate.
Results of polyphosphate impact and/or orthophosphate impact
indicated: measurable increase of P with treatment time;
localized concentration of P coating cap;
displacement of Si;
migration; and,
mineral precipitation is
possible over time.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 430 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 7 |
| Published : | 11/01/2007 |
