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AWWA WQTC59006
- Evaluation of Different Ozonation Strategies and of Temperature Effects on Biological Filter Performance
- Conference Proceeding by American Water Works Association, 11/02/2003
- Publisher: AWWA
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The results obtained during this study reinforced the potential of ozonation/biofiltration tocontrol organics, ozone byproducts (OBP) and chlorinated disinfection byproducts(DBP) formation precursors. A total of six halaoacetic acids (HAA6) and total trihalomethanes(TTHM) measured in the filters were in compliance with Stage 1 of theDisinfection Byproduct Rule. Most substrates were removed within 3 minutes of emptybed contact time (EBCT) and, in general, additional contact times contribute very little toenhance biofilter performance. Dissolved organic carbon (DOC) was removed up to30% and high removal of ozone byproducts was obtained in all filters (i.e., 65 to 84%),regardless of temperature regime. Implementation of second-stage ozonation resulted insignificant ozone savings while maintaining similar CT credit and biofilter performancethan first-stage biofiltration. Optimization of ozone oxidation placement in the treatmenttrain resulted in a reduction of 20% in applied ozone. Biomass and microbial activitymeasurements correlated well with filter performance. Filters operated at coldtemperatures performed as well as the ambient filters, after proper acclimation. Includes 10 references, tables, figures.