The objective of
this AwwaRF-sponsored research project (#3107) is to determine the effect of changing
disinfectants (free chlorine to chloramines and vice versa) on metals release from lead, brass, and
copper components in the distribution system. This project also is studying the effects of
galvanic 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 HDR
ARTC facility in Bellevue, Washington, and in the District of Columbia Water and Sewer Authority (DCWASA) facility in Washington, D.C. for the purpose
of testing the effects of changing disinfectants in waters with varying water quality
characteristics. At each of the 2 test facilities, 4 pipe loop systems were used to test the
following pipe materials: unpassivated lead; copper; bronze; and, passivated lead. For each of
these pipe loop systems, 3 short coupons (each 2 inches in length) were used for electrochemical
measurements and 1 longer coupon (18 inches in length) was used as a source of metals release
for grab sampling. In addition to the single-metal pipe loops, 3 galvanic coupled pipe loop
systems were assembled at each test facility (Bellevue, Washington and Washington, D.C.) to investigate
the effects of galvanic couplings (lead/copper; lead/bronze; and copper/bronze) on metals release
associated with the change in disinfectant. Water quality parameters (pH, alkalinity, phosphate
addition) were modified and controlled during the change in disinfectant testing. The Project
Team also performed fill-and-dump testing of brass components and field sampling during a
routine "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.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 2 MB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 33 |
| Published : | 11/01/2008 |
