Application of an ozonation-adsorption-ultrafiltration system for surface water treatment

Investigations are presented on the effect of the preliminary ozonation on ultrafiltration (UF) and powdered activated carbon (PAC)/UF process performance, especially on permeate flux decline and the effectiveness of model organics removal. Flat membranes from regenerated cellulose were used. A model solution was prepared as a mixture of humic acids and phenol. PAC dosage was equal to 100 mg/l(-1). The ozone dosages were in the range of 1-3 mg O-3 l(-1) (0.2-0.6 mg O-3/mg TOC). It was found that the most advantageous configuration was preliminary ozonation with an ozone dosage of 0.4 mgO(3)/mg TOC-UF. The permeate flux reached a value equal to the pure water flux value. Moreover, a very high effectiveness of model organics removal was obtained: TOC was reduced by about 96% and UV254 absorbance was removed completely. When PAC was added to the feed containing humic acids without ozonation, a drop in a permeate flux was observed compared to UF. Similarly, the addition of PAC to feed treated with ozone resulted in a significant drop in the permeate flux in comparison with pure water flux, regardless of ozone dosage applied.