AWWA ACE68967

The objective ofthis AwwaRF-sponsored research project (#3107) is to determine the effect of changingdisinfectants (free chlorine to chloramines and vice versa) on metals release from lead, brass, andcopper components in the distribution system. This project also is studying the effects ofgalvanic coupling and existing scales on metals release during a change in disinfectant.Two innovative re-circulating pipe loop systems were developed and assembled in the HDRARTC facility in Bellevue, Washington, and in the District of Columbia Water and Sewer Authority (DCWASA) facility in Washington, D.C. for the purposeof testing the effects of changing disinfectants in waters with varying water qualitycharacteristics. At each of the 2 test facilities, 4 pipe loop systems were used to test thefollowing pipe materials: unpassivated lead; copper; bronze; and, passivated lead. For each ofthese pipe loop systems, 3 short coupons (each 2 inches in length) were used for electrochemicalmeasurements and 1 longer coupon (18 inches in length) was used as a source of metals releasefor grab sampling. In addition to the single-metal pipe loops, 3 galvanic coupled pipe loopsystems were assembled at each test facility (Bellevue, Washington and Washington, D.C.) to investigatethe effects of galvanic couplings (lead/copper; lead/bronze; and copper/bronze) on metals releaseassociated with the change in disinfectant. Water quality parameters (pH, alkalinity, phosphateaddition) were modified and controlled during the change in disinfectant testing. The ProjectTeam also performed fill-and-dump testing of brass components and field sampling during aroutine "chlorine burn" in the DCWASA distribution system. This paper provides a discussion of testing results and consideration of Pb(II)/Pb(IV)and Cu(I)/Cu(II) theory as applied to metals release in the distribution system. Includes tables, figures.

Product Details

Edition:

Vol. - No.

Published:

11/01/2008

Number of Pages:

33

File Size:

1 file , 2 MB