|Title||DAF treatment of a reservoir water supply: Comparison with in-line direct filtration and control of organic matter|
|Publication Type||Journal Article|
|Year of Publication||1995|
|Authors||Schmidt P.D., Tobiason JE, Edzwald JK, Dunn HJ|
|Journal||Water Science and Technology|
|Keywords||assimilable organic carbon, direct filtration, disinfection by-products, dissolved air flotation, dissolved organic carbon, Ozonation|
The goal of this paper is to compare the performance of an in-line direct filtration (no flocculation) process with a dissolved air flotation (DAF) and filtration process for drinking water treatment. Both processes were studied at the pilot scale and included biologically active dual media (GAC/sand) rapid filters. Specific attention is given to the fate of organic matter. Organic matter was analyzed by measurements of dissolved organic carbon (DOC), assimilable organic carbon (AOC), disinfection by-product formation potential (DBPFP) and ultraviolet absorbance at 254 nm (UV254). In general, flotation removed a large fraction of organic matter with additional removal provided by biologically active filters. Most of the work occurred with ozonation of the raw water (pre-ozone). Ozone increased the biologically assimilable fraction of the water; filtration decreased this fraction to acceptable levels. Overall, effects of ozone on other organics are relatively small.