Method for treating waste water and recovering resources in acrylic fiber production

A method of treating wastewater and recovering resources in acrylic fiber production, comprising the following steps:

• A) filtering wastewater from water-washing and filtering unit of acrylic fiber plants by a filter to intercept and recover high-molecular-weight polymer contained therein, and then returning the recovered polymer back to the acrylic fiber production and adding the recovered polymer into the finished product, optionally, reusing part of filtered wastewater in the water-washing and filtering unit;
• B) removing non-interceptable high-molecular-weight polymer in the wastewater by subjecting the wastewater from step A) to coagulation and air floatation treatment;
• C) introducing the effluent from step B) into biological treatment unit and adding polyvalent metal ions as an adsorption promoter to increase the removal of non-biodegradable organics in the biological treatment unit, where the polyvalent metal ions are selected from the group consisting of calcium ions, magnesium ions, aluminum ions and a mixture thereof, and the amount added is 5 to 100 mg/L;
• and
• D) removing the organics remaining in the effluent from the biological treatment unit after step C) by an advanced treatment, wherein the advanced treatment is selected from the group consisting of any combinations of oxidation, coagulation, precipitation and air flotation.