AWWA WQTC62367

This slide presentation outlines information on an annular reactor study on the effectiveness of ClO₂ in controlling biological growth in open-air basins. The objectives of the study included: studying the effectiveness of ClO₂ in controlling biological growth in open air basins (HPC, AODC, Chlorophyll-a); compare Cl₂ and ClO₂; and, chlorite, chlorate, bromate, disinfection byproduct formation. Results of the study include: both continuous and intermittent ClO₂ potentially at least as effective as Cl₂ in controlling biological growth; about 70 µg/L AOX and 25 µg/L TTHM due to Cl₂ ; TTHM <10 µg/L for ClO₂; and, bromate formation below detection limit. Also, a pilot study is discussed that studied the effect of pre-ClO₂ on: coagulation, settled turbidity, UV-absorbance, TOC; ozonation, UV-absorbance, residual ozone, DBP; and, filtration, particle count, headloss, turbidity.