Bromate ion (BrO3
-) is a disinfection
byproduct that is produced when
raw water containing bromide ion
(Br-) is ozonated. BrO3- is a concern
for water utilities because it has been classified
as a class II carcinogen, and the US
Environmental Protection Agency has established
a maximum contaminant level (MCL)
of 10 ug/L for it in finished water.
This study evaluated sulfite ion (SO3
2-)
and reduced iron (Fe2+) as potential removal
agents for BrO3- over a wide pH range. The
experimental rate law for BrO3- removal
using SO3
2- shows that the rate of removal
decreases with increasing pH. The experimental
rate law for BrO3- removal using Fe2+
shows that the rate of removal increases with
increasing pH.
The study found that under drinking water
conditions, SO3
2- is not an effective BrO3-
removal agent. However, at drinking water
pH (pH > 7), Fe2+ is a good BrO3- reducing
agent. The expanded rate law for BrO3-
removal using Fe2+ predicts that at pH 8,
100 ug/L BrO3- is removed in 2 min. The
study also found that the use of pickling Fe as
the source of Fe2+ has the advantage of providing
additional ferric ion for flocculation.
(Fe2+ is produced during the pickling of
steel, when concentrated hydrochloric acid is
used to clean the surface of a sheet of steel.)
Most current strategies regarding BrO3-
address the prevention of its formation.
This study shows that the capability to
remove BrO3- permits water utilities that
have high Br- concentrations in their source
water to use stronger oxidants in high concentrations
without exceeding the BrO3-
MCL of 10 ug/L. The chemical removal
process using Fe2+ also has the advantages
of not being as complicated or expensive as
current alternative technologies. Includes 30 references, tables, figures.
| Edition : | Vol. 94 - No. 2 |
| File Size : | 1
file
, 420 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 8 |
| Published : | 02/01/2002 |
