OZONATION OF URBAN WASTEWATER

A municipal wastewater secondary effluent from a biological treatment was ozonated in order to study the efficiency in the organic micropollutants removal and in the simultaneous changes of the effluents organic matter characteristics. Two ozone doses based in the amount of dissolved organic carbon (DOC), around 2.6 and 13 mg O-3/mgDOC, were applied, and the effluent was analyzed before and after ozonation. Ozone confirmed its efficiency in terms of micropollutant reduction when applied to the municipal biotreated effluent. Furthermore, organic matter transformation was also investigating through the evolution of lumped parameters as chemical oxygen demand (COD), dissolved organic matter (DOC), UV254 absorbance and the fate dissolved organic fractions by means of size exclusion chromatography followed by organic carbon detection. According to the results obtained, it was observed that the oxidation of micropollutants competes with the oxidation of the bulk of organic matter and this organic matter was converted into more biodegradable, less aromatic and smaller substances.