高浓度液晶废水处理研究

STUDY ON TREATMENT OF HIGH CONCENTRATION LIQUID CRYSTAL WASTEWATER

针对某化工厂液晶中间体生产废水,采用Fenton预处理+水解酸化+好氧+超滤反渗透工艺进行处理,发现Fenton技术具有良好的预处理效果,对COD的去除率在50%左右,且废水可生化性从原水的0.05提高至0.38,经过水解酸化及好氧单元的降解,废水ρ(COD)可降至150~200 mg/L,再通过超滤反渗透膜处理,COD浓度可降至50mg/L以下,达到GB/T 19923—2005《城市污水再生利用—工业用水水质》要求,出水可用作稀释水或厂内冷却用水。膜浓水通过自主研发的强化蒸发装置处理,可实现废水不外排。采用该工艺对厂内实际生产废水进行现场调试运行,处理规模为5 m^3/d,原水初始pH值为2.0~4.5,ρ(COD)为7 000~10 000 mg/L。稳定运行后,生化段出水pH值为7.5~8.0;ρ(COD)为150~200 mg/L,膜处理后ρ(COD)<50 mg/L,证明运行稳定可靠。

In the paper, the liquid crystal intermediate wastewater from a chemical plant was treated, using Fenton pretreatment ＋ hydrolysis acidification ＋ aerobic ＋ ultrafiltration and reverse osmosis process. The result showed that Fenton method had a good pretreatment effect,and its removal rate of COD was about 50%; the B/C value of the raw water was increased from 0. 05 to 0. 38; after hydrolysis degradation acidification and aerobic unit,COD was reduced to 150 ～ 200 mg/L; then after the ultrafiltration and reverse osmosis membrane,COD dropped to less than 50 mg/L,which was bordered the Regeneration and Utilization of Urban Sewage： Water Quality of Industrial Water（National Standard）,and could be used as dilution water or circulating cooling water. Concentrated liquid of the membrane was treated by an evaporation device instead of drained out. In the debug course for this combined process with a sewage treatment scale of 5 tons/day,the original pH of the wastewater was 2. 0 ～ 4. 5,COD concentration was 7 000 ～ 10 000 mg/L. When the system run stable,the pH of the effluent of biochemical segment was 7. 5 ～ 8. 0,and COD concentration was 150 ～ 200 mg/L; while in the effluent of membrane,COD dropped to less than 50 mg/L.