Investigation And Application On The Treatment Technology For Dry-spun Polyacrylonitrile Fiber Wastewater

The dry-spun polyacrylonitrile (PAN) fiber wastewater cannot be discharged directly before treatment. In this paper, the treatment of PA fiber wastewater was studied after a lot of investigation of the industrial technology and discharge status. Based on the analysis and summary of the research methods and present situation of this treatment both domestic and abroad, it is concluded that all the technologies applied to industrialization for treating highly concentrated PA fiber wastewater have not been ideally effective. It is very difficult to make PA fiber wastewater reach the discharge standard. The ways to deal with the problem include internal electrolysis, chemical oxidation, flocculation experiment, anaerobic process, aerobic process, nitration, active-carbon adsorption and so on. Experiments of laboratory-scale and pilot-scale on treating PA fiber wastewater with chemical oxidation, flocculation experiment, anaerobic process, aerobic process, nitration, active-carbon adsorption have been conducted.The main pollutants in the dry-spun PA fiber wastewater include nitrile, ester, alkane, phenol and so on. The organic compound with long carbon chain and some polymer will depress the biochemical capacity of the acrylic fiber wastewater. It is necessary to treat the wastewater with both physicochemical method and biochemical treatment. All the above measures are effective to the acrylic fiber wastewater. The methods of chemical oxidation and flocculation experiment have effect on improving the biochemical capacity of wastewater; COD removal rate can increase to 45.39%. The advantage of anaerobic process is making the macromolecule into small molecule which can be degraded easily by hydrolysis-acidification, the COD removal rate can be 33.58%. The aerobic process with microorganism can remove the organic compound effectively. The active-carbon adsorption is suitable to the diluent PA fiber wastewater. The degradation of COD can be decreased 250mg/L from 800mg/L with the multiplex technologies of chemical oxidation, flocculation, anaerobic process, aerobic process, nitration and active-carbon adsorption, which can meet the discharge standard of PA fiber industry.