Nitrification is a common problem faced by utilities
using chloramines for distribution system residual maintenance.
Nitrification involves the growth of ammonia-oxidizing
bacteria and the resulting production of
nitrite, which exerts a chloramine demand. This can
lead to a sometimes precipitous loss of chloramine.
Once nitrification becomes established, it can be difficult
to bring under control. This study was undertaken
to help develop tools for dealing with nitrification.
This article assesses the usefulness, using both
bench- and full-scale data, of a previously proposed
criterion of 0.05 mg/L nitrite-nitrogen as a critical
threshold for confirming nitrification in chloraminated
distribution systems. In this study, the investigators
found that this level of nitrite-nitrogen has value in
detecting nitrification, but that the 0.05 mg/L nitrite-nitrogen
level is too high to predict nitrification before
it becomes well established. A loss of total chlorine or
monochloramine residual, however, could give early
warning of a potential nitrification episode.
The authors conclude that, for utilities concerned
about nitrification, multiple water quality parameters
should be analyzed simultaneously, if possible, to
develop time-series trends specific to a given water
utility. If adequate resources are not available to test
for a suite of parameters, total chlorine residual data
can serve as an early warning sign of potential nitrification.
Drops in total chlorine residual should then instigate
additional, targeted analyses (such as nitrite and
ammonia, among others). Includes 24 references, tables, figures.
| Edition : | Vol. 97 - No. 7 |
| File Size : | 1
file
, 340 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 14 |
| Published : | 07/01/2005 |
