Method for deep treatment of complex industrial wastewater by utilizing nano-zero-valent iron

The invention relates to a method for deep treatment of complex industrial wastewater by utilizing nano-zero-valent iron. The method is designed for solving the current problems of complex ingredients in the industrial wastewater, high pollutant concentration, unstable water quality and the like. According to the method disclosed by the invention, a multi-stage series-connected nano-zero-valent iron reaction device is adopted for performing deep treatment on the complex industrial wastewater, wherein the nano-zero-valent iron is recycled in the device and can perform stage-by-stage backward flow in the device. The nano-zero-valent iron reaction device containing 2-5 stages is arranged according to the number of species and the concentration of the pollutants in the actual wastewater. During the treatment process, the pH of each stage is controlled by adding an acid/base and increased stage by stage, the oxidation-reduction potential (ORP) of each stage is controlled by dosing/refluxing the nano-zero-valent iron and decreased stage by stage, and the wastewater can be effectively treated after multi-stage reaction/separation. The various pollutants in the wastewater can be removed stage by stage and step by step, the reaction conditions of each state are controllable, and the water quality of outlet water is stable and reaches the standard; and simultaneously, the utilization rate of the nano-zero-valent iron is improved, and the method is suitable for deep treatment of various types of the complex industrial wastewater.