The carboxyl nitrile hard glue wastewater contains raw materials, by-products and some auxiliary materials that are not fully involved in the reaction, and has the characteristics of high chemical oxygen demand (COD), high mass concentration of Pull apart powder（BX）, high viscosity and toxicity, resulting in the poor operation of the water treatment process. The pretreatment process with "air flotation, membrane separation and ozone oxidation" as the core was adopted to remove COD and decoking powder from carboxyl nitrile hard adhesive wastewater, so as to improve the biodegradability of wastewater. This pretreatment process had problems such as rubber caking and blocking, filter device blocking and so on, and the overall operation effect was poor. The pretreatment process was improved by increasing the influent flow rate to 105 m3/h, increasing the chemical backwash time and backwash frequency, adjusting the ozone quality concentration to 35 mg/L, and decreasing the height of the packing layer of the ozone catalyst layer to 650 mm. The results show that when the effluent COD is stable at about 1 100 mg/L, the mass concentration of BX is maintained at about 40 mg/L, and BOD/COD (BOD is the ratio of biological oxygen demand) is about 0.30, the influent conditions of the subsequent process can be met, and the stable operation of the system can be ensured.
