AWWA WQTC69319

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 coagulantchanged from alum to PACl, isolated cases of leadpoisoning;Dodrill & Edwards (1995): more lead with higherchloride and lower sulfate;pH measured as low as 3.4 at solder surface(Triantafyllidou, 2007); and,Triantafyllidou (2007) proved galvanic corrosioncan 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 testwaters;water was changed twice per week and collected asweekly composite samples; and,weekly composites were analyzed for lead (and othermetals) as well as Cl- and SO₄^2-. Experimental results indicated the following: the best condition was at pH 7.3 with orthophosphate; and,Virginia Tech made the recommendation to changeinhibitor from polyphosphate blend to ortho. Includes figures, tables.

Product Details

Edition:

Vol. - No.

Published:

11/01/2008

Number of Pages:

45

File Size:

1 file , 2 MB