AWWA JAW56402

Bromate ion (BrO3-) is a disinfectionbyproduct that is produced whenraw water containing bromide ion(Br-) is ozonated. BrO3- is a concernfor water utilities because it has been classifiedas a class II carcinogen, and the USEnvironmental Protection Agency has establisheda maximum contaminant level (MCL)of 10 ug/L for it in finished water.This study evaluated sulfite ion (SO32-)and reduced iron (Fe2+) as potential removalagents for BrO3- over a wide pH range. Theexperimental rate law for BrO3- removalusing SO32- shows that the rate of removaldecreases with increasing pH. The experimentalrate law for BrO3- removal using Fe2+shows that the rate of removal increases withincreasing pH.The study found that under drinking waterconditions, SO32- is not an effective BrO3-removal agent. However, at drinking waterpH (pH > 7), Fe2+ is a good BrO3- reducingagent. The expanded rate law for BrO3-removal using Fe2+ predicts that at pH 8,100 ug/L BrO3- is removed in 2 min. Thestudy also found that the use of pickling Fe asthe source of Fe2+ has the advantage of providingadditional ferric ion for flocculation.(Fe2+ is produced during the pickling ofsteel, when concentrated hydrochloric acid isused 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 toremove BrO3- permits water utilities thathave high Br- concentrations in their sourcewater to use stronger oxidants in high concentrationswithout exceeding the BrO3-MCL of 10 ug/L. The chemical removalprocess using Fe2+ also has the advantagesof not being as complicated or expensive ascurrent alternative technologies. Includes 30 references, tables, figures.

Product Details

Edition:

Vol. 94 - No. 2

Published:

02/01/2002

Number of Pages:

8

File Size:

1 file , 420 KB