EESS talk on "The End of the Pipe: Using Aquatic Chemistry to Control Lead Concentrations in Tap Water"

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Event details

Date and time 24.11.2020 12:1513:00  
Place and room
ZOOM
Speaker Dr Daniel Giammar, professor, Aquatic Chemistry Laboratory, McKelvey School of Engineering, Washington University in St.Louis, USA
Category Conferences - Seminars
Abstract:
The legacy of lead-containing materials used for water supply poses challenges to tap water quality.  In contrast to drinking water contaminants that have their origins in the source water and can be removed at a treatment plant, the source of lead in drinking water is the pipe that connects a home to the water main and the plumbing within the home.  Concentrations of lead in tap water are governed by the chemical reactions between the water in the pipe and the scale of solid phases that develops on the inner surface of the pipe.  Perturbations of the water chemistry have resulted in high profile crises of lead in drinking water (e.g., Washington, DC and Flint, Michigan).  However, adjustment of the water chemistry is also a lever that can be used to minimize lead release to drinking water.

Bench-scale and pilot-scale experiments have explored the influence of water chemistry on lead in drinking water.  The effectiveness of orthophosphate as a corrosion inhibitor and its impact on the composition and structure of pipe scales was evaluated in a series of bench-scale experiments with lead pipes.  The responses of the lead pipes were examined for scenarios involving (1) orthophosphate addition in advance of a change in disinfectant from free chlorine to chloramine and (2) application of orthophosphate at a pH value higher than the range over which it is typically used.  The formation and stability of lead(IV) oxide (PbO2), a low solubility solid that is only stable in the presence of free chlorine, is an example of the importance of oxidation-reduction reactions.  Redox reactions are also relevant to the galvanic corrosion that can occur during partial lead service line replacements.  More recent work is exploring the influence of the blending of reclaimed wastewater and conventional sources on lead release.

Short biography:
Professor Giammar is the Walter E. Browne Professor of Environmental Engineering in the Department of Energy, Environmental and Chemical Engineering at Washington University in St. Louis.  Professor Giammar's research focuses on chemical reactions that affect the fate and transport of heavy metals, radionuclides, and other inorganic constituents in natural and engineered aquatic systems.  His recent work has investigated the removal of arsenic and chromium from drinking water, control of the corrosion of lead pipes, geologic carbon sequestration, and biogeochemical processes for remediation of uranium-contaminated sites.  Professor Giammar is currently an Associate Editor of Environmental Science & Technology.  Professor Giammar completed his B.S. at Carnegie Mellon University, M.S. and Ph.D. at Caltech, and postdoctoral training at Princeton University before joining Washington University in St. Louis in 2002.
 

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Practical information

  • General public
  • Free
  • This event is internal

Organizer

  • EESS - IIE

Contact

Tags

Lead Drinking Water Corrosion Control Aquatic Chemistry Phosphate

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