Compared with chlorination with sodium hypochlorite, chlorine dioxide has several advantages. It is efficacious at lower concentrations; does not produce trihalomethanes (its by-products are sodium chloride and sodium chlorite); is not affected by pH or ammonia; and requires only short treatment duration and thus has less effect on system operations (Tsou et al. 1995). Some reports suggest that chlorine dioxide may be more effective than chlorine against adult mussels (Rusznak, Mincar, and Smolik 1994; Garrett and Laylor 1995; Matisoff, Brooks, and Bourland 1996). It has been used as a disinfectant for water for several decades. Disadvantages include the requirement for onsite generating equipment; storage of the component precursor chemicals (sodium hypochlorite and hypochloric acid); high oxidant demand, which may require higher treatment rates and reduce efficacy on the mussels; and conversion of the dioxide to chlorite, which limits the amount of ClO2 that can be applied without excessive chlorite discharge.
Chemical Name and Formulations
Field Instructions and Guidance on Operational Applications