Acrylic fiber waste water treatment method

An acrylic fiber waste water treatment method. An acrylic fiber waste water treatment method is provided which comprises the following steps: (a) performing ultrasonic hydrolysis treatment of acrylic fiber waste water; (b) treating the acrylic fiber waste water treated by ultrasonic hydrolysis in step (a) in a biological reaction tank; and (c) performing Fenton treatment of the acrylic fiber waste water obtained in step (b). Through ultrasonic hydrolysis pretreatment of the acrylic fiber waste water, oligomers and long-chain macromolecules which are difficult to bio-degrade in the waste water are decomposed and degraded; the COD index of the waste water is decreased obviously; and the biodegradability is improved. Effluent from ultrasonic hydrolysis flows into the integrated biological reaction tank for biological reactions such as denitrification and decarbonization so as to remove most COD and ammonia nitrogen. Effluent from the integrated biological reaction tank is subjected to the Fenton process to remove residual organic matter difficult to degrade so as to ensure the effluent quality.