In order to comply with the maximum contaminant levels for trihalomethanes (THMs)
and haloacetic acids (HAAs), many utilities are utilizing alternative disinfectants, such as chlorine
dioxide (ClO<sub>2</sub>) and chloramines (NH<sub>2</sub>Cl). The use of ClO<sub>2</sub> in bench- and demonstration-scale
tests was found to produce no THMs or trihalogenated HAAs, or only trace amounts, but
it did form low levels of dihalogenated HAAs (DXAAs). In the presence of bromide, brominated
DXAA species formed. Post-chloramination did not stop THM formation in waters
high in total organic carbon and/or bromide. THM formation in the presence of NH<sub>2</sub>Cl was of
the order of 20 percent of the amount that would have formed in the presence of free chlorine.
Because ClO<sub>2</sub> is a strong radical oxidant, it can form oxidation byproducts similar to
those formed by ozone (carboxylic acids, aldoketoacids, aldehydes), but ClO<sub>2</sub> typically forms
byproducts at lower levels (on a weight basis) than ozone. The formation of carboxylic acids,
especially oxalate, increased with increasing ClO<sub>2</sub> demand. Secondary byproducts from postdisinfection
(e.g., haloacetaldehydes) also formed. Includes 22 references, table, figures.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 380 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 15 |
| Published : | 11/02/2003 |
