Many effective technologies have been developed and approved for ballast water treatment, and the effectiveness of a process should be evaluated considering its environmental friendliness. The aim of this study was to evaluate the formation and formation mechanisms of bromate (BrO3−) and chlorate (ClO3−) in seawater during ozonation, electrolysis, and a combined (ozonation/electrolysis) process. In seawater ozonation, BrO3− was generated exceeding a 5 mg/L ozone dose despite the high Br− (65 mg/L). The formation of BrO3− and ClO3− by electrolysis depended on the electrode materials where two types of electrodes (IrO2/Ti and Pt/Ti) were used. The combined (ozonation/electrolysis) process generated much higher levels of BrO3− and ClO3− than either individual process. In ozonation or electrolysis, mixed oxidant including HOCl/OCl− and HOBr/OBr− is the main parameter for inactivation, which is called total residual oxidant, TRO. In this study, a predictive model for BrO3− and ClO3− was suggested in terms of TRO formation. This predictive model can recommend allowable TRO (generated by ozonation or electrolysis) for practical applications in seawater treatment.
Bibliographical noteFunding Information:
This work is supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIP) (2013R1A2A2A05006466) and Korea Ministry of Education (MOE) as “BK21 PLUS Project.”
© 2014, Copyright © 2014 International Ozone Association.
All Science Journal Classification (ASJC) codes
- Environmental Engineering
- Environmental Chemistry