AWWA ACE65112

The changes in the polarity of natural organic matter (NOM) across two water treatment configurations, conventional treatment (coagulation, flocculation, sedimentation and filtration) and conventional treatment with pre-ozonation and biofiltration were analyzed at pilot-scale using the polarity rapid assessment method (PRAM). The pilot plant had two parallel treatment trains, which allowed for the characterization of both processes simultaneously and minimized the temporal variability of the influent water. The use of the polarity rapid assessment method (PRAM) offered the advantage of evaluating variations in NOM character and reactivity under ambient conditions after filtration. Results showed temporal variations between polarity on the raw influent samples as well as differences in the specific chemistry of the NOM through each treatment. Overall, ozone/biofiltration reduced non-polar and polar NOM, whereas the effect of conventional treatment varied between samples. In some cases, the changes in polarity caused by conventional treatment produced NOM of similar polarity to the ozone/biofiltration train. Ozonation was shown to decrease the hydrophobicity and increase the polarity of NOM. These results suggest the influent NOM variability should be considered and monitored as these changes result in differences in NOM removal and reactivity. Includes 36 references, table, figures.