Optimization of ozonation process for removal of micropollutants in urban wastewater

Abstract

This study aims to extend the existing theoretical knowledge to the practical application of ozonation in advanced wastewater treatment. Urban wastewater from a WWTP in a European developed country (Austria) was treated by ozonation technology with different specific doses, varying from 0 g O3 to 1.0 g O3/g dissolved organic carbon (DOC), observing an abatement of micropollutants and bromate formation. Based on the ozonation, micropollutants were categorised into 3 groups, namely highly-reactive, medium-reactive, and non-reactive. For ozonation, micropollutants were removed at >80% for three groups at various ozone doses of 0.6 - 1.0 g O3/g DOC. The results showed that different bromate formations were observed in accordance with different ozone doses and varying between the investigated effluent samples. Bromate formation ranged between 0.65 ± 0.28 and 11.22 ± 9.85 µg/L. The value of ozone dose was regulated by WHO for drinking water (10 µg/L) was only exceeded at > 0.88 ± 0.05 g O3/g DOC, which is higher than normal applied doses for micropollutant removal (0.6 - 0.7 g O3/g DOC).