Posttreatment aeration to reduce THMs.

Autor: BROOKE, ETHAN, ROBIN^COLLINS, M.
Předmět:
Zdroj: Journal: American Water Works Association; Oct2011, Vol. 103 Issue 10, p84-96, 13p, 1 Color Photograph, 3 Diagrams, 6 Charts, 4 Graphs
Abstrakt: 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. [ABSTRACT FROM AUTHOR]
Databáze: Supplemental Index