One third of respondents in a survey of U.S. water
utilities reported using or planning to use
chloramines for secondary disinfection, primarily to
maintain a disinfectant residual and minimize formation
of disinfection byproducts (DBPs). However,
nitrification is a problem in chloraminated systems.
Nitrification has been controlled via breakpoint chlorination -
periodic switching from chloramines to
free chlorine - but the consequences of this strategy
are not well understood. The authors evaluated the
effects of a one-month switch from chloramines to
free chlorine. They concluded that disinfectant
switching alone will terminate nitrification but is
unlikely to provide long-term nitrification control.
Systems that have used chloramines for a long time
are more likely to have nitrification problems. Cast-iron
pipe also might increase nitrification potential.
Potential negative effects of disinfectant switching
include increased DBP concentrations and periods of
low disinfectant residual. These results can help utilities
decide whether or how to use disinfectant switching
as a nitrification control strategy. Includes 38 references, tables, figures.
| Edition : | Vol. 100 - No. 10 |
| File Size : | 1
file
, 910 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 12 |
| Published : | 10/01/2008 |
