Removal of Bromate and Perchlorate in Ozone/GAC Systems

Influent:
CUW
10-50 ug/L Bromate
pH 6.8-8.2
2-14mg/LDO
0.3 - 42 mg/L Nitrate
t
NOTE: Not to Scale
2.5-cm Inner-Diameter
8.0-cm BAC Bed Height
Support
Material
Figure 2.1 Schematic of BAG filters using CUW
For the filter being operated with an influent nitrate concentration of 5.0 mg/L and a 25-minute
EBCT, the last two weeks of this experiment showed 81 ± 6 percent bromate removal. The
consistent bromate removals observed in these filters demonstrated the attainment of steady state.
New filters were not assembled for each experimental condition (i.e. DO concentration, nitrate
concentration, EBCT). Therefore, zero bed volumes is a term relative to the start of the particular
experiment, not necessarily to the overall life of the filter. Each experimental condition was run for
approximately 2 weeks, to ensure adequate acclimation to the experimental conditions.
Figure 2.2 shows a schematic diagram of another set of filters that was constructed to
evaluate bromate reduction using LMW. Norit 830 GAC (Norit Americas Inc., Atlanta, GA) was
the medium in these filters, and it was taken from the full-scale plant at the Paul M. Neal Water
Treatment Facility (Lake Bluff, IL). This carbon had and average particle diameter of 0.9 mm and
had been used for approximately seven years to treat ozonated LMW. Prior to packing the carbon
into the column, the BAC was rinsed with DDW to remove excessive turbidity. Since this carbon
was already biologically active, no extensive preloading period was required. For some of the LMW
experiments, a syringe pump (74900 series, Cole Farmer Instrument Co., Vernon Hills, IL) was used
to add an electron donor solution containing 1.2 mM
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