Preconditioned method coking wastewater

The invention discloses a pretreatment method of coking wastewater. The method which comprises procedures of pH adjustment, internal electrolysis, Fenton oxidation and coagulating precipitation concretely comprises the following steps: 1, adding an acid to an adjustment pool provided with wastewater to form an acidic solution to allow the pH of the wastewater to be between 2.7 and 3.3; 2, injecting the wastewater into the upper part of an internal electrolysis reactor by a pump, and carrying out the internal electrolysis; 3, allowing effluent water of the internal electrolysis reactor to flowinto an Fenton oxidation reactor, adding the acid with continuously stirring to the pH of the effluent water of 3-3.5, adding solid ferrous sulphate to the concentration of ferrous ions of 700-900ppm, adding a hydrogen peroxide solution to make the concentration of hydrogen peroxide reach 1500-1900ppm; and 4, allowing wastewater to flow into a coagulation-precipitation tank after finishing the Fenton oxidation, adding a coagulant aid with stirring, standing to precipitate and treating a supernatant obtained after precipitation as pretreated coking wastewater.