Treatment method of pickle dipping water

The invention relates to a biochemical treatment method of pickle factory wastewater. The pickle factory wastewater comprises pickle dipping water and other comprehensive wastewater, wherein in the pickle dipping water, the COD is 500000-60000 mg/L, the total nitrogen is 2000-4000 mg/L, the total phosphorus is 400-600 mg/L, and the salt content is 10-15%; and in the other comprehensive wastewater,the COD is 200-300mg/L, and the salt content is 0.8-1.0%. The specific treatment method comprises the following steps: S1, sequentially carrying out ultrafiltration, primary nanofiltration, neutralization treatment, secondary nanofiltration and evaporative crystallization on pickle steeping water, collecting trapped fluid of primary nanofiltration and secondary nanofiltration and condensate of evaporative crystallization, and mixing to obtain a pretreated mixed solution; S2, mixing the pretreated mixed solution with other comprehensive wastewater, wherein the specific ratio of the pretreatedmixed solution to the othe