Halogenated disinfection byproducts (DBPs) may undergo reduction reactions at the corroded pipe wall in drinking water distribution systems consisting of cast or ductile iron pipe. Iron pipe corrosion products were obtained from several locations within two drinking water distribution systems. Crystalline-phase composition of freeze-dried corrosion solids was analyzed using X-ray diffraction, and ferrous and ferric iron contents were determined via multiple extraction methods. Batch experiments demonstrated that trichloronitromethane (TCNM), a non-regulated DBP, is rapidly reduced in the presence of pipe corrosion solids and that dissolved oxygen (DO) slows the reaction. The water-soluble iron content of the pipe solids is the best predictor of TCNM reaction rate constant. These results indicate that highly reactive DBPs that are able to compete with oxygen and residual disinfectant for ferrous iron may be attenuated via abiotic reduction in drinking water distribution systems.
Bibliographical noteFunding Information:
The authors acknowledge the financial support provided by the American Water Works Research Foundation (Project 2990) and the National Science Foundation (Grant no. BES-0332085). CRP was supported by an EPA STAR Graduate Fellowship. Thanks are extended to Brad Eilts and Jim Bode of St. Paul Regional Water Services and Joel Emke of the Steven's Point Water Utility for their assistance in collecting the pipe samples. We also thank Prof. R. Lee Penn for the use of her XRD and the reviewers for their helpful comments.
- Corrosion solids
- Disinfection byproducts
- Dissolved oxygen
- Drinking water