This powerpoint presentation begins by providing a brief overview of the chloramination issue of nitrification, factors affecting nitrification, trihalomethane (THM) cometabolism, and chloroform cometabolism. Research goals included: examining
the role THMs play in preventing
nitrification; and,
improving the ability to predict nitrification episodes
based, in part, on background THM
concentrations. The experimental approach included the following:
four annular reactors simulate distribution
system -- inner cylinder rotates to create
hydraulic shearing force;
parameters were
Lake Austin (tap) water culture and
typical drinking water conditions;
pH 7-9;
Ammonia -- 0.5 to 1 mg/L NH<sub>3</sub>-N;
Chlorine -- 1 to 3 mg/L as Cl<sub>2</sub>; varied THM concentrations and bromine
incorporation ratio; set up two identical reactors with the only
difference being the presence of THMs;
monitor effluent ammonia, nitrite, and
monochloramine concentrations;
nitrification indicated by
presence of nitrite (NO<sub>2</sub><sup>-</sup>),
decrease in ammonia concentration, and
loss of monochloramine residual; and,
compare nitrification onset between control
reactors and THM reactors. Presentation conclusions indicate that:
THMs have a measurable effect on
nitrification at drinking water conditions, and THMs slowed onset of nitrification;
nitrification occurs in the presence of THMs
under drinking water conditions;
trends generally agreed with Nitrification Index (NI) model; and,
predictive power would likely improve if
disinfection kinetics were better understood. Includes figures.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 800 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 28 |
| Published : | 11/01/2008 |
