Removal of Bromate and Perchlorate in Ozone/GAC Systems

Table 1.2 Bromate removal in CUW at pH 7.5 with different influent nitrate concentrations
Influent Effluent
# EBCT DO NO3- BrO3" DO NO3' % BrO3'
(min) (mg/L) (mg/L) (ug/L) (mg/L) (mg/L) removal
4 25 2.2 0.2 21 0.1
5 25 2.3 5.1 20 0.1
0.9 86
5.7 76
6 49 2.2 0.2 21 0.2 2.7 95
7 50 2.3 5.1 20 0.2 8.1 93
(Adapted from Journal AWWA, 91(8), 74-84.)
1 0 -|
ao
_c
•a o.s -
1
3 •s uo 0.6 -
-•-5. 1 mg/L influent nitrate (Expt. 5)
— E3-0.2 mg/L influent nitrate (Expt. 4)
1 Q 0.4 -
u
m
1
1
—— m ———— 76% removal
-2 0.2 - • B -» Q_ ^-,
8
LJ 0
u 86% removal
[•y , /•> /\
D D
U.U i i i i i
i i
0 200 400 600 800
Bed Volumes
1000 1200 1400
Figure 1.4 Effect of influent nitrate concentration on bromate breakthrough from a BAG filter
(initial conditions: CUW, EBCT - 25 minutes, pH 7.5, 2.3 mg/L DO, 21 pg/L BrO3")
(Adapted from Journal AWWA, 91(8), 74-84.)
DO in the filters. Figures 1.5 and 1.6 show nitrogen mass balances, including ammonia, nitrite, and
nitrate, for Experiments 4-7. A few of the points show that the effluent nitrogen is greater than the
influent nitrogen by less than 0.1 mg/L as N. This is within the experimental error of the analytical
methods used. In general, the influent nitrogen values agreed quite well with effluent nitrogen values,
except for Experiment 6 (Figure 1.6). Since effluent nitrogen was less than influent nitrogen for this
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