The invention discloses a pretreatment technology for high-concentration
refractory organic
petrochemical wastewater. The technology comprises steps as follows: (1) the organic
petrochemical wastewater is acidized until the pH ranges from 4 to 5, then the organic
petrochemical wastewater is heated to the temperature of 80-95 DEG C, and wastewater A is obtained through
solid-liquid separation after
precipitation of
silicate; (2) iron and
copper plates are added to the wastewater A for microelectrolysis for 0.5-2 h, then wastewater B is obtained through
solid-liquid separation, the pH of the wastewater B is adjusted to range from 2.0 to 2.5, a
hydrogen peroxide solution accounting for 0.5%-3% of the wastewater B in volume is added, the
mass fraction of the
hydrogen peroxide solution is 25%-40%, a reaction is performed for 1-3 h, and wastewater C is obtained; (3) after the pH of the wastewater C is adjusted to range from 2.5 to 3.5, the wastewater C is subjected to three-dimensional electro-Fenton treatment for 1-3 h, then a flocculating agent is added after the pH is adjusted to range from 9.5 to 10.5 by alkaline liquor, and wastewater D is obtained after
solid-liquid separation; (4) the pH of the wastewater D is adjusted to range from 1.5 to 3.5, a catalyst and
persulfate are added, the mixture is irradiated by
ultraviolet light and aerated for photocatalytic oxidation for 1-2 h, and the pretreatment of the wastewater is completed. With the adoption of the technology, the COD (
chemical oxygen demand) value of the wastewater is effectively decreased, and the biodegradability of the wastewater is improved.