This powerpoint presentation begins by providing a brief overview of pilot test protocols that included: constructed test loops at 5 sites;
loops contained four 6 in. long segments of: 3/4 in. lead pipe, 3/4 in. copper tube with 5 in. long bead of 50/50 lead-tin solder, and 1/4 in. diameter bar of leaded brass in 3/4 in. PVC; water flow was 5 gpm (3.6 fps) in each of 3 parallel legs;
fed identical phosphate doses (based on plant PO4 dose) in
each leg with high zinc concentration (1:1 or 1:3 ZOP), low
zinc concentration (1:10 ZOP), or no zinc (75% PO4);
used a 10-hr stagnation period nightly; and,
operated each loop for six months. A summary of corrosivity results is provided, along with a summary of water quality results. Study conclusions indicate that: overall, zinc does not appear to have a substantial impact on
corrosivity of lead, copper or mild steel;
zinc does not appear to play a role in protection of steady-state
metal release from piping materials, its role in the
release of particulates, especially lead is unclear; and,
at locations where differences were statistically significant,
no clear pattern emerged - sometimes zinc improved
performance, sometimes it hindered performance. Includes tables, figures.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 1.3 MB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 26 |
| Published : | 11/01/2009 |
