AWWA WQTC60731

This work investigated the effect of bromide and iodide ions on the formation andspeciation of disinfection byproducts (DBPs) from chlorination of natural waters. Twowaters containing contrasting group precursors were chlorinated after being spiked withvarious levels of bromide or iodide ions (0-30µM/L). The molar yields of trihalomethanes (THMs) and haloacetic acids(HAAs) increased as the initial bromide ion concentration increased. The molar yield ofTHMs was comparatively stable for different initial iodide ion concentrations. Nosignificant change of total organic halogen (TOX) concentration was found for varying bromide concentrations.However, TOX concentrations decreased substantially with increasing initial iodide ionconcentrations. The increasing of initial bromide concentrations resulted in decreasinglevels of unknown TOX (i.e. not attributed to THMs and HAAs) and unknown TOCl butincreasing unknown TOBr. The distribution among tri-, di- and monohalogenated HAAswas dependent of the bromide ion concentrations. Increasing initial bromideconcentration resulted in higher fraction of trihalogenated HAAs and lower fraction ofdihalogenated HAAs. The general order of the bromine incorporation factor was:TTHM>THA&DHAN>DHA. The general order of the extent of bromine substitutionwas: DHAN> DHA&TTHM >THA. The extent of iodine substitution was much lowerthan that of bromine substitution when comparing identical initial concentrations since asubstantial amount of iodide was oxidized to iodate. Increasing chlorine dose was able tocontrol the formation of iodinated organic compounds by oxidizing the majority of iodideto iodate. Includes 29 references, table, figures.

Product Details

Edition:

Vol. - No.

Published:

11/15/2004

Number of Pages:

20

File Size:

1 file , 590 KB