Nitrification affects many water utilities that use chloramine
as the finished water disinfectant, but traditional nitrification
control strategies are not always effective. Although
the utility can change from chloramine disinfection to free chlorine
to control nitrification, the disinfection byproducts (DBPs) produced
by free chlorination are just as problematic as the nitrification.
With increased use of chloramination to meet the requirements
of the Disinfectants/DBP Rule, nitrification will become an
issue for more utilities.
Skadsen reviewed historical water quality data and the occurrence
of nitrification in the Ann Arbor, Mich., water system and
saw a correlation between high pH and low occurrence of nitrification.
If this correlation held true during full-scale operation at
the Ann Arbor water plant, raising the pH of finished water might
be a relatively simple alternative for preventing nitrification.
Successful experiments prompted the utility to set an operational
goal of pH 9.3 for its finished water and to conduct an
eight-year assessment to evaluate the effects of the higher pH
on the occurrence and degree of nitrification. The elevated pH
significantly improved the control of nitrification but did not
completely eliminate it. This experience indicates that raising
finished water to pH 9.3 is a practical step for controlling nitrification,
although additional control methods may be required in
some cases. Includes 32 references, tables, figures.
| Edition : | Vol. 94 - No. 7 |
| File Size : | 1
file
, 230 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 11 |
| Published : | 07/01/2002 |
