Lead corrosion control from lead, copper‐lead solder, and brass coupons in drinking water employing free and combined chlorine

Abstract

The U.S. Environmental Protection Agency (EPA) promulgated the Lead and Copper Rule (LCR) in 1991, establishing 0.015 mg/L as the lead action level in drinking water. Public water suppliers must optimize water characteristics to meet this requirement at the consumer's tap. In this study, bench‐scale experiments were completed to evaluate the effects of employing either free and combined chlorine on two alternative corrosion control strategies: pH adjustment and inhibitor addition, using treated water from two different water supplies. In addition, the effect of fluoride on lead corrosion was investigated. Lead, copper/lead‐solder, and brass coupon tests were employed. For lead and copper/lead solder, free chlorine produced higher lead levels than combined chlorine at different pH. However, for brass coupons at different pH as well as copper/lead solder and brass using several commercial corrosion inhibitors, combined chlorine released more lead than free chlorine. In all cases, higher water pH was effective at minimizing dissolved lead, as were the inhibitor additions. Furthermore, this study also showed that addition of both free chlorine as well as fluoride increase lead corrosion.

Key words:

• Lead
• Brass
• Corrosion
• Combined Chlorine