Root Zone Wastewater Treatment (RZWT) is an option of natural wastewater treatment widely studied throughout the world, being a technology based on physical, chemical and biological processes. However, there are some attributes in effluent that occasionally are not eliminated by RZWT. In this context, the use of ozone may contribute to mineralization, disinfection, detoxification, and, especially, color and turbidity removal. Ozone is an excellent oxidant, with great potential to reduce color, turbidity and other attributes in liquids, such as in wastewater treatment. This paper evaluated the effect of different ozone exposure times (0, 30, 60, 90, 120 and 150 minutes) and the application of different dosages of ozone (0, 4, 10, 17, 25 and 35 mg L-1 of O3) on Hydrogeonic Potential (pH), Electrical Conductivity (EC), Dissolved Oxygen (OD), Total Alkalinity (Alk.), Sodium (Na) and Potassium (K) in domestic sewage effluent treated by the RZWT. Different exposure times and ozone dosages did not influence the attributes Potassium, Sodium, Ammonia and Total Solids. Color and turbidity decreased, while pH, Alkalinity and Dissolved Oxygen increased at all exposure times and O3 dosages in relation to the non-ozonized effluent.
