Double-reflux denitrification membrane-bioreactor (MBR) process for treating dry acrylic fiber waste water

The invention belongs to a double-reflux denitrification membrane-bioreactor (MBR) process for treating dry acrylic fiber waste water, mainly aiming at treatment of high organic nitrogen with denitrification requirement and petrified dry acrylic fiber waste water which is difficult to degrade. The process comprises the following steps: feeding petrified dimethylformamide (DMF) dry acrylic fiber waste water into a front anoxic pool 2 from a water inlet 1, converting partial organic nitrogen into ammonia nitrogen under the anoxic condition, carrying out denitrification on a nitration liquid 10 refluxing to the front anoxic tank 2 by fully utilizing a waste water carbon source, and simultaneously compensating basicity 3 to the waste water; and then feeding entering the waste water into an aerobic pool 4, carrying out organism aerobic oxidation, organic nitrogen aerobic oxidation and ammonia nitrogen nitration under the abundant basicity, wherein the effluent contains a large amount of nitrates; refluxing the partial effluent to the front anoxic pool 2 for denitrification, and feeding the other effluent into a membrane separation pool 7; carrying out denitrification by utilizing an additionally arranged carbon source; and sucking with a micro-filter membrane assembly 8 so as to generate effluent 9, and refluxing a sludge concentrated liquid 11 to the front anoxic pool 2. The process is high in nitrogen removal efficiency.