Effects of preozonation on the adsorbability and the biodegradability of aquatic humic substances and on the performance of granular activated carbon filters

Abstract

Previous work carried out with test organic substances and under sterile and non-sterile conditions of filtration allowed us to show that the microbial degradation of biodegradable compounds increased the GAC adsorption capacities for non-biodegradable solutes (De Laat et al., 1985). This research extends the work to higher molecular weight compounds (isolated aquatic humic and fulvic acids, PHA and PFA) and evaluates the effects of a preozonation treatment on the performances of GAC filters. In the first part of this study, the effect of ozonation on some physical and chemical properties (carboxyl content, adsorbability on GAC, u.v.-absorbance) and on the biodegradability of humic substances were investigated. In the second part, GAC column filtrations were operated under sterile and non-sterile conditions in order to show the influence of preozonation treatment on the performance of GAC columns and to determine the parts due to adsorption and to biodegradation in DOC removal.