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 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 SO₄^2-. 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.