AWWA JAW39270

Utility experience under the Lead and Copper Rule was examined to provide improved insight into corrosion control. Average 90th percentile lead concentrations were highest in very low alkalinity water (<30 mg/L as CaCO3) at utilities that did not use inhibitors; lead release was significantly reduced at higher alkalinities. Average lead releases were 20-90 percent lower for utilities using phosphate inhibitors (orthophosphates, polyphosphates, and blended phosphates) in very low alkalinity waters than for utilities not using inhibitors. At alkalinities of 30-74 mg/L as CaCO3 and at pH values > 7.40, it appeared that polyphosphate inhibitors had adverse effects on average lead release. Utilities with pH < 7.40 and high alkalinity waters had the highest copper concentrations. Phosphate inhibitors were usually beneficial in mitigating copper release; however, most benefits were at utilities with pH < 7.80 and alkalinity > 90 mg/L as CaCO3. Inhibitors appeared to adversely affect average copper release in some pH and alkalinity categories. Includes 23 references, tables, figures.

Product Details

Edition:

Vol. 87 - No. 7

Published:

07/01/1995

Number of Pages:

12

File Size:

1 file , 890 KB