The efficiency of ozone treatment in the degradation of organic compounds of nuclear laundry water is presented. Ozonation experiments were performed in different combinations of pH, hydrogen peroxide and ultraviolet radiation. The degradation of non-ionic surfactant and other organic compounds was analysed by chemical oxygen demand, total organic carbon, biochemical oxygen demand and the molecular weight distribution measurements. The optimal degradation circumstances were found to be at pH 7 with ozone, UV radiation and hydrogen peroxide addition. The transfer of ozone increased substantially thus resulting in decreased treatment time compared to our previous experiments. The reductions of chemical oxygen demand, total organic carbon and biochemical oxygen demand were about 46%, 32% and 70%, respectively.