Biomembrane treatment method of two-step wet-spun acrylic fiber wastewater

Abstract

The invention relates to a biomembrane treatment method of two-step wet-spun acrylic fiber wastewater. In the method, anaerobic reaction and aerobic reaction are adopted. Being treated by the method, the DMAC two-step wet-spun acrylic fiber wastewater, originally having the following technical indexes: 500-1,000mg / L of COD (chemical oxygen demand), 75-100mg / L of NH4-N, 50-100mg / L of DMAC (dimethyl acetamide), 0-120mg / L of acrylonitrile and pH of 6.0-9, have the following technical indexes: not more than 250mg / L of COD, not more than 4mg / L of NH4-N, not more than 2mg / L of DMAC, not more than 2.0mg / L of acrylonitrile and pH of 6.0-9. The method provided by the invention has the following advantages: the excess sludge is less, the process flow is short, and the method is suitable for treating the mixed wastewater in the two-step wet spinning production taking DMAC as a solvent as well as for treating the wastewater in spinning production adopting other solvents, the wastewater containing acrylonitrile and partial printing and dyeing, spinning and petrochemical wastewater.

Description

technical field [0001] The invention relates to a method for treating chemical fiber wastewater, in particular to a method for treating mixed wastewater in acrylic fiber production. Background technique [0002] There are 16 acrylic fiber production enterprises in China, with a total production capacity of 831,100 tons / year. Currently, there are 12 companies in operation, with a total production capacity of 801,000 tons / year. Four processes are mainly used: sodium thiocyanate (NaSCN) solvent one-step wet spinning ( Zibo Shandong Xueyin Company) 10,000 tons / year, sodium thiocyanate (NaSCN) solvent two-step wet spinning (Shanghai Petrochemical Company Acrylic Fiber Division, Daqing Petrochemical Company Acrylic Fiber Factory, Anqing Petrochemical Branch Acrylic Fiber Factory, Daqing Refining and Chemical Company Acrylic fiber factory) 321,000 tons / year, N, N dimethylformamide (DMF) solvent two-step dry spinning (Fushun acrylic fiber factory, Qilu Petrochemical acrylic fiber fa...

AI Technical Summary

Problems solved by technology

If the wastewater is directly discharged, it will seriously affect the water quality of the receiving water body and endanger biological safety.

The treatment process adopted by most of the acrylic fiber wastewater treatment plants in enterprises is pretreatment + anaerobic + aerobic, and the COD of the effluent is generally 200-400mg / L, which cannot meet the standard of direct discharge. Enterprises generally mix the effluent into chemical fiber mixed wastewater for treatment The plant is mixed with other wastewater and then discharged, which leads to the following problems in the wastewater treatment process: (1) The toxic organic substances contained in the acrylic wastewater affect the operation of the biological treatment system, and some toxic organic substances "penetrate" into the wastewater treatment system into the affected wastewater The receiving water body affects the water quality of the receiving water body; (2), the sulfate radical in the wastewater is too high, which affects the working efficiency of the biological treatment system, and the sulfate radical in the effluent is not up to the standard; (3), the refractory organic matter (such as some additives) increases The difficulty of the wastewater treatment system, the COD of the effluent of the acrylic wastewater treatment plant cannot meet the national discharge requirements; (4), a variety of nutrients need to be added during the wastewater treatment process, and the remaining sludge must be treated, which increases the cost of wastewater treatment

All these research results do not involve the treatment of waste water produced by two-step wet spinning with DMAC as the solvent; the core of the technology is the activated sludge biological treatment method, which requires a large amount of residual sludge to be discharged regularly, and the cost of secondary treatment is high; the process is long , complex operation and inconvenient management

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