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Posttreatment aeration to reduce THMs
Author(s) -
Brooke Ethan,
Collins M. Robin
Publication year - 2011
Publication title -
journal ‐ american water works association
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.466
H-Index - 74
eISSN - 1551-8833
pISSN - 0003-150X
DOI - 10.1002/j.1551-8833.2011.tb11550.x
Subject(s) - aeration , nozzle , chlorine , environmental science , environmental engineering , trihalomethane , water treatment , chemistry , pulp and paper industry , waste management , engineering , mechanical engineering , organic chemistry
Posttreatment aeration inside water tanks or in chlorine contact basins to strip trihalomethanes (THMs) after formation is an underused and cost‐effective treatment option to reduce disinfection by‐products. In this study, diffused aeration achieved removal rates of 9 to > 99.5%, depending on air‐to‐water ratio, water temperature, and THM species. Spray aeration–a more efficient process–achieved THM reductions of 20 to > 99.5%, depending on droplet diameter, droplet travel distance, water temperature, and THM species. Droplet diameter is an important design variable and is controlled by operating pressure and nozzle characteristics. Droplet travel distance, however, exerted a greater influence on THM removals. The average droplet diameter and travel distance variables can be developed into a unit air‐to‐water volumetric ratio that can be used to reasonably predict total THM removals. Free chlorine does not appear to be reduced by aeration because only a small fraction of it will be amenable to removal in a closedsystem environment.