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Characterization of TOX Produced During Disinfection Processes

Water Research Foundation, 11/1/2001-10/31/2004

The purpose of this research was: (1) to determine the best TOX protocol for use with ion chromatography (IC) analysis for the purposes of discriminating between TOCl, TOBr and TOI. (2) to determine the nature and chemical characteristics of the unknown fraction of the total organic halogen (UTOX) produced during chlorination and alternative disinfection processes (i.e., chloramination, chlorine dioxide, ozone disinfection), and (3) to assess the impact of treatment on removal of UTOX precursors.

PIs: Reckhow & Hatcher
Post Doc: Junsung Kim
Students: Guanghui Hua, Sarah A.L. Caccamise and Rakesh Sachdeva

Proposal and Reports

  • Proposal
  • Progress Reports
  • Final Report: Reckhow, David A., Hua, Guanghui, Kim, Junsung, Hatcher, Patrick G., Caccamise, Sarah A. L., and Sachdeva, Rakesh. Characterization of TOX Produced During Disinfection Processes.  2007. Denver, CO, American Water Works Association Research Foundation.

Journal Publications based on this work

Conference presentations based on this work

  • Hua, G., and DA Reckhow, “Determination of TOCl, TOBr, and TOI in Drinking Water by Pyrolysis and Off-line Ion Chromatography”, Proceedings of the Water Quality Technology Conference.  2004, AWWA, Denver, CO.
  • Hua, G., and DA Reckhow, “Effect of Bromide and Iodide Ions on the Formation and Speciation of DBPs During Chlorination”, Proceedings of the Water Quality Technology Conference.  2004, AWWA, Denver, CO.
  • Hua, G.., DA Reckhow, “Characterization of Unknown TOX Precursors based on Hydrophobicity and Molecular Size”, Proceedings AWWA Annual Conference, June 12-16, 2005; San Francisco, CA.
  • Hua, G., and DA Reckhow, “Determination of TOCl, TOBr, and TOI in Drinking Water by Pyrolysis and Off-line Ion Chromatography”, oral presentation, Water Quality Technology Conference.  November 16, 2004, San Antonio, TX.
  • Hua, G., and DA Reckhow, “Effect of Bromide and Iodide Ions on the Formation and Speciation of DBPs During Chlorination”, oral presentation, Water Quality Technology Conference.  November 17, 2004, San Antonio, TX.
  • Hua, G.., DA Reckhow, “Characterization of Unknown TOX Precursors based on Hydrophobicity and Molecular Size”, oral presentation, AWWA Annual Conference, June 12-16, 2005; San Francisco, CA.
  • Sachdeva, R., PG Hatcher, S. Kim, AG Marshall, RP Rogers and DA Reckhow, „Characterization of Total Organic Halogen (TOX) Produced During Disinfection Processes by ESI-TOF MS and ESI-FTICR MS“ poster presentation, EMSI/North Central NOM Workshop, Columbus, OH, June 15-17, 2005
  • Hua, G.., DA Reckhow, “Comparison of total organic halogen formation from various disinfection processes”, oral presentation, Water Quality Technology Conference,  November 6-10, 2005 (TUE1); Quebec City, Que.
  • Hua, G.., DA Reckhow, “Factors affecting the formation and destruction of TOX in drinking water”, oral presentation, Water Quality Technology Conference,  November 6-10, 2005; Quebec City, Que.
  • Hua, G, and DA Reckhow, “Comparison of total organic halogen formation from chlorine and alternative disinfectants” oral presentation at the AWWA Annual Conference, June 12, 2006, San Antonio, TX
  • Hua, G, and DA Reckhow, “Hydrophobicity and molecular size distribution of unknown halogenated disinfection byproducts in drinking water” oral presentation at the Water Quality Technology Conference,  , November 6, 2006, Denver, CO

Theses/Dissertations based on this work

diffusers

Background: Total organic halide (TOX) is an analytically defined measurement that is often applied to environmental waters, especially drinking waters.  The intent of the TOX measurement is to provide an estimate of the total amount of organically-bound (i.e., by covalent C-X bonds) chlorine, bromine and iodine in a dilute water sample.  The standard method for measuring TOX does not allow for separate determination of the various halogen species.  Alternative TOX methods capable of differentiating between the halogens (i.e., TOCl vs TOBr vs TOI) are of interest to the water industry, because of the perceived toxicity of bromine and iodine containing disinfection byproducts.

This work was conducted in several phases; and it built upon the latest fundamental advancements in NOM characterization.  First, a series of TOX methodology studies were undertaken.  This was needed to validate existing TOX methods before they could be reliably applied to the analysis of TOBr and TOI.  Next, a survey of selected North American utilities was conducted.  This involved the collection of waters of diverse quality and geographic location for laboratory treatment with 5 basic disinfection scenarios (chlorination, chloramination, both with and without preozonation, and chlorine dioxide).  Analysis of these samples for TOX species and known DBPs was undertaken to help the researchers better assess the full range of UTOX occurrence and the raw water characteristics that are associated with higher levels.  In addition, distribution system samples were fractionated according to hydrophobicity and molecular size, and then analyzed for UTOX.  The next task focused on factors influencing UTOX concentrations, especially engineering factors.  This task was designed to examine impacts of chemical conditions during disinfection on ultimate UTOX concentrations.  The final phase was directed to the application of advanced chemical techniques (borrowed from the humic substances research field) to the characterization of UTOX.  A set of innovative techniques were explored for assessing UTOX on a molecular level.  Most prominent among these was electrospray ionization fourier transform ion cyclotron resonance mass spectrometry (ESI-FT-ICR-MS).


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