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Secondary effects of anion exchange on chloride, sulfate, and lead release: Systems
approach to corrosion control
Rich picture showing the link between corrosion processes: (A) global drivers such as climate change, (B) water source
variability including alternative water sources, (C) advanced treatment and secondary changes in water chemistry, (D)
distribution system with emphasis on iron-based pipes, and (E) household plumbing with emphasis on lead.
This research was funded by a SEAGEP
undergraduate research award to HW and
faculty start-up funds to THB. We would like
to thank Stephanie Ishii, Kelly Landry, and
Alicia Sendrowski for their assistance with
sampling and experiments. We also
appreciate the support of Cedar Key, Palm
Springs, St. Cloud, and Yankeetown water
treatment plants for assistance with sample
collection. Hillary Willison (B.S., 2011) Dr. Treavor H. Boyer
Overview and Objectives
Manipulating water chemistry to reduce the corrosivity of water and to promote the formation of low-solubility mineral scales is
a common approach to corrosion management. Special attention, however, must be given when implementing a new water
treatment process or adjusting an existing process if water chemistry is used for corrosion control. Treatment modifications can
change the chemistry of finished water, thus increasing metal leaching in the distribution system and in household plumbing. The
goal of this research was to provide an improved understanding of the chloride-to-sulfate mass ratio (CSMR) considering
chloride and sulfate variations at full-scale water treatment plants and corrosion potential under simulated premise plumbing
conditions. The specific objectives of this work were: (1) to determine the effect of varying chloride and sulfate concentrations at
constant CSMR on lead and copper release; (2) to determine the effect of low levels of natural organic matter (NOM) at constant
CSMR on lead and copper release; and (3) to track the changes in chloride, sulfate, and NOM through full-scale magnetic ion
exchange (MIEX) treatment.
Conclusions
High concentrations of chloride and sulfate yielded significantly greater lead release than low concentrations of
chloride and sulfate at constant CSMR of ~0.5 and Suwannee River NOM at ~1.5 mg C/L under galvanic corrosion.
The presence and type of organic material played an important role in lead leaching, and to a lesser extent copper
leaching. Two model organic compounds, salicylic acid and tryptophan, had a negligible effect on lead release as
compared with NOM isolated from the aquatic environment.
Full-scale MIEX treatment systematically increased the chloride concentration, decreased the sulfate concentration, and
increased the CSMR of the finished water. The secondary changes in water chemistry caused by MIEX treatment, and
anion exchange in general, are expected to increase the corrosion potential of treated water, especially for lead.
A systems framework that spans global drivers affecting water quality, household plumbing, and all treatment steps in
between is needed to understand and control corrosion related to drinking water.
Willison, H., Boyer, T.H., 2012. Secondary effects of anion exchange on chloride, sulfate, and lead release: Systems approach to
corrosion control. Water Research, 46 (7), 2385–2394. doi: 10.1016/j.watres.2012.02.010
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Treavor H. Boyer, Ph.D. ~ Assistant Professor ~ Department of Environmental Engineering Sciences ~ University of Florida
[email protected] ~ 352.846.3351 ~ www.ees.ufl.edu/homepp/boyer ~ www.twitter.com/WaterWeUpTo
