This powerpoint presentation begins by providing a brief overview of the chloride to sulfate mass ratio. Causes for concern include the following: high CSMR;
Pb action level exceeded when coagulant
changed from alum to PACl, isolated cases of lead
poisoning;
Dodrill & Edwards (1995): more lead with higher
chloride and lower sulfate;
pH measured as low as 3.4 at solder surface
(Triantafyllidou, 2007); and,
Triantafyllidou (2007) proved galvanic corrosion
can increase Pb release by 16 X or more. Topics covered include the Origin of Effect -
Galvanic Corrosion, and distribution system altering of CSMR. Three bench-scale case studies examined the following:
1" lengths of 50:50 Pb:Sn solder were placed inside 1"
copper couplings and exposed to 100 mL of test
waters;
water was changed twice per week and collected as
weekly composite samples; and,
weekly composites were analyzed for lead (and other
metals) as well as Cl- and SO<sub>4</sub><sup>2-</sup>. Experimental results indicated the following: the best condition was at pH 7.3 with orthophosphate; and,
Virginia Tech made the recommendation to change
inhibitor from polyphosphate blend to ortho. Includes figures, tables.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 2 MB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 45 |
| Published : | 11/01/2008 |
