AWWA ACE68866

This powerpoint presentation begins by presenting a review of causes for concern that include the following:Pb action level exceedance when coagulantchanged from alum to PACl;Dodrill & Edwards (1995)- more lead withhigher chloride and lower sulfate;pH as low as 3.4 at solder surface(Triantafyllidou, 2007); and,Triantafyllidou (2007) proved galvaniccorrosion increased Pb release by 16 X. Possible origin of effect is presented, along with a mechanistic study of Patuxent River water. Presentation conclusions indicate the following:lead solder-copper couples sustained veryhigh lead levels throughout the study;low pH measured at anode;Anions (Cl- and SO₄^2-) migrate to the leadanode;lead sulfate is relatively insoluble, whilechloride complexes lead and increases leadleaching; and,increased lead levels correlated withincreased galvanic current;galvanic effects are very persistent in somesystems; and,high orthophosphate or high alkalinity donot eliminate galvanic effects, but canreduce them. Includes figures.

Product Details

Edition:

Vol. - No.

Published:

11/01/2008

Number of Pages:

40

File Size:

1 file , 1.9 MB