Purification treatment method of liquid containing harmful substance, and purification treatment device of liquid containing harmful substance for carrying out said method

A purification treatment method of a liquid containing a harmful substance, and a purification treatment device of a liquid containing a harmful substance for carrying out said method are provided which enable efficient purification treatment of a liquid containing a harmful substance by using dissolved ozone, which is an oxidizing agent with excellent safety. In this purification treatment methodof a liquid containing a harmful substance and purification treatment device of a liquid containing a harmful substance for carrying out said method, dissolved ozone is added and mixed into a liquidcontaining a harmful substance; thereafter, said liquid is brought into contact with a transition metal-containing oxide which has a BET specific surface area of 80m2/g or greater and which adsorbs ozone and adsorbs the harmful substance; and oxidation of the harmful substance by the dissolved ozone is promoted to perform highly efficient oxidative decomposition. 本发明提供含有害物质液体的净化处理方法及用于实施该方法的含有害物质液体的净化处理装置，所述方法使用作为安全性高的氧化剂的