AWWA ACE70782

This powerpoint presentation begins by providing a brief overview of tastes and odors (T&O) in developed countries. A flavor profile analysis of Boussy St Antoineraw and chlorinated water (Dec 1985) is presented, along with THM's identified by SDE-GC-MS (BoussySt Antoine, Dec 1985). Topics presented include: Weber-Fechner curve for Iodoform andBromoform (medicinal descriptor); literature review of odor thresholds forvarious THM (FPA method: 45ºC); Vernouillet case study ofchlorination of groundwater containingammonia; role of ammonia in iodinated THMformation (Gittelman and Yohe, 1989); Cassan Treatment Plant (December1996); taste intensity as a function of chlorine dose; Cassan case study conclusion; compared formation of iodoforms (µg/L) withchlorine and chlorine dioxide (La Falaise groundwater); formation mechanism ofiodinated THMBichsel et al., 1999HOI/OII-I; iodides in the environment; analytical methods for iodides and iodoTHMs and I-HAAs; and, identification of iodoacetic acid in methylated acidicextract (Bordeaux area, July 1994) duringmedicinal odor episode. Conclusions indicate that: medicinal taste and odor episodes caused byiodinated DBP's have been observed at dozens of sitesscattered throughout France;all of them were observed in groundwaterscontaining 20-100 µg/L of iodides and disinfected withchlorine only (chloramines are not allowed in France);iodoacids not investigated but detected on oneoccasion; most iodoform problemswere solved by switchingfrom chlorine to chlorinedioxide;chloramination whereammonia is added beforechlorine or at the sametime encouragesformation of iodinatedspecies;larger contact times (> 5minutes) with chlorinebefore ammoniationreduces formation ofiodinated species; and,removing the iodide precursorswith a strong oxidant prior todisinfection may be the bestoption. Includes tables, figures.

Product Details

Edition:

Vol. - No.

Published:

11/01/2009

Number of Pages:

23

File Size:

1 file , 1.3 MB