AWWA WQTC60656

Chlorine dioxide (ClO₂) may be considered by utilities as an alternative disinfectant to ozone andchlorine to comply with disinfection requirements set by the Surface Water Treatment Rule andto control disinfection byproduct (DBP) formation. However, very little is known regarding the formation of biodegradableorganic matter (BOM) by ClO₂ and its effect on the distribution system.Pilot-scale testing was conducted to determine the potential for ClO₂ preoxidation to produceBOM while treating blends of California State Project water and Colorado River water.Preoxidation was followed by conventional treatment (coagulation, flocculation, sedimentation)and parallel filtration processes (chlorinated and biologically active). The addition of ClO₂increased the formation of formaldehyde, carboxylic acids, and assimilable organic carbon(AOC). Carboxylic acid and AOC levels following ClO₂ were generally lower when comparedto previously conducted work with ozone, whereas formaldehyde levels were higher.Biofiltration reduced the level of BOM. Annular reactors (ARs) were placed downstream offiltration to simulate water flow through a distribution system (with a detention time of 6 h).Biomass measurements in the AR following ClO₂ and biological filtration were similar tomeasurements taken in the AR following conventional chlorine treatment. Includes 16 references, table, figures.

Product Details

Edition:

Vol. - No.

Published:

11/15/2004

Number of Pages:

11

File Size:

1 file , 470 KB