Effect of ozonation on sorption of natural organic matter by biofilm

Experiments were conducted to determine the effects of ozonation on sorption of aquatic natural organic matter (NOM) onto biofilm using bench-scale packed-bed reactors. It was found that 18–22% of NOM measured as dissolved organic carbon (DOC), and 28–30% measured as chloroform formation potential, was removed from the water without biodegradation. The bulk of the NOM removal was attributed to biosorption of low-molecular-weight compounds—less than 3000 Da. At a dose of 1 g-O3/g-DOC, ozonation was not found to have a significant effect on biosorption of NOM. Ozonation simultaneously decreased the molecular size and increased the acidity of NOM compounds, and it was concluded that the effects counterbalanced each other at an ozone dose of 1:1, resulting in no significant change in NOM sorption.