Formation of haloacetic acids, halonitromethanes, bromate and iodate during chlorination and ozonation of seawater and saltwater of marine aquaria systems

This manuscript addresses identification, analysis, formation and occurrence of key disinfection byproducts (DBPs) formed during chlorination and/or ozonation of both natural seawater (NSW), and synthetic high- and low-bromide saltwater (HBSW and LBSW, respectively). In this study, several groups of water disinfection byproducts were studied, including haloacetic acids (HAAs), halonitromethanes (HNMs), bromate and iodate. Three different water systems were studied including filtered natural seawater (NSW, ca. 64.9 mg L−1 Br−), a high-bromide (Br−) saltwater (HBSW, ca. 24.8 mg L−1 Br), and low-Br− saltwater (LBSW, ca. 4.3 mg L−1 Br). Because ozone reacts with Cl− to form free chlorine in seawater and salt water systems, similar DBP patterns were observed for both chlorine and ozone oxidants. The results revealed that some HAAs and HNMs are formed at greater than 100 μg L−1 concentrations and are greatly affected by water constituents and formulations when treated with chlorine and ozone. The results showed that in low-Br− water salt water, chlorinated HAAs and HNMs predominated, while much greater concentrations of brominated HAAs and HNMs were produced in both natural and synthetic higher Br− saltwater. Concentrations of bromate and iodate were strongly impacted by factors other than Br− and I− concentrations including whether the system was open or closed.

► Created methods for haloacetic acids and halonitromethanes in seawater and saltwater.
► Determined HAAs and HNMs in full scale aquaria with widely varying bromide concentrations.
► Determined effect of chlorine and ozone on HAA, HNM, bromated and iodate formation.
► Provided key information on controlling DBPs in seawater and saltwater aquaria.