Study On Treatment Of Wet-Spun Acrylic Fiber And Acryl Amide Mixed Waste Water

The composition of wastewater from the production process of wet-spun acrylic is complex, containing high-concentration COD, sulfate and sulfite, as well as dimethylacetamide (DMAC) and acrylonitrile (AN), and the wastewater is one of the typical high-concentration and refractory industrial wastewater. A variety of physical and chemical methods include plasma electrolysis, MVR, Fenton oxidation, and the combined processes of plasma electrolysis-SBR and Fenton oxidation-SBR were firstly used to treat acrylic fiber wastewater from the process of industrial production. A pilot-scale study on the mixed wastewater from the production of wet-spun acrylic fiber and acryl amide were performed using the combined process of coagulating sedimentation, IC and A/O. Meanwhile, a laboratory-scale experiment on the combined process of coagulating sedimentation, two-phase anaerobic process and A/O was also conducted.Treatment efficiency of acrylic fiber wastewater was evaluated using plasma electrolysis, MVR, Fenton oxidation process, the combined processes of plasma electrolysis-SBR and Fenton oxidation-SBR. The results show that MVR process could not be applied into practical engineering because of expensive cost and difficult treatment to concentrated liquid. Meanwhile the other processes could not also meet the discharge standard.A pilot-scale study on the mixed wastewater from the production of wet-spun acrylic fiber and acryl amide were performed using the combined process of IC and A/O. The results show that effluent COD is about1000mg/L, NH3-N is less than50mg/L, and the removal efficiency is about67%and85%respectively, under the condition that the proportion of acrylic fiber wastewater account for50%of mixed wastewater, influent COD of the system is about4000mg/L, and the content of NH3-N is100-130mg/L. The process shows strong shock resistance and stable treatment efficiency.Two-phase anaerobic process and A/O process were conducted to treat the mixed wastewater from wet-spun acrylic fiber and acryl amide producing processes. The experimental results indicate that influent COD of the system was about4000mg/L, effluent COD were240-280mg/L,450-480mg/L and640-680mg/L respectively, and the removal rates of COD were91%-94%,85%-88%and80%-83%respectively, under the condition that HRT of acidification reactor, methane producing reactor and A/O pool were20h,36h and24h respectively, and the volume of acrylic fiber wastewater accounted for30%,50%and70%of total mixed wastewater volume respectively. In conclusion, two-phase anaerobic process and A/O process are most appropriate to treat mixed wastewater of acrylic fiber and acrylamide. And when the ratio of acrylic fiber wastewater and acrylamide wastewater is1:1, it can achieve the three-grade criterion of integrated wastewater discharge standard (GB8978-1996). The research results have important guiding significance for the practical engineering of this kind of wastewater treatment.