印染废水的节能型中水回用系统研究

Research on Energy Saving Reclaimed Water Reuse System of Printing and Dyeing Wastewater

摘要: 针对双膜法(超滤 + 反渗透)工艺处理印染废水时存在高能耗、高污染、高清洗频率等“三高”问题，设计一种印染废水节能型中水回用系统，该系统由深度预处理单元和膜单元组成。深度预处理过程中，选择PAC为絮凝剂，PAC的投加量为100 mg/L，最佳絮凝pH值为7.0；臭氧催化氧化反应时，臭氧的投加量30 mg/L，氧化时间为30 min。废水经深度预处理后，进膜水质达到设计要求，膜系统污堵减少、清洗频率降低。膜单元采用独特的膜系统工作方式及带有自调型能量回收装置，使得膜运行过程的能耗大幅下降，还能减少反渗透浓差极化现象。在工程运行中，膜单元的吨水电耗总和为1.38~1.40 kw∙h。

Abstract: An energy saving reclaimed water reuse technology of printing and dyeing wastewater was designed to address the “three highs” problems of high energy consumption, high pollution and high cleaning frequency in the treatment of printing and dyeing wastewater using the dual membrane method (ultrafiltration + reverse osmosis). The system consisted of advanced pretreatment unit and membrane unit. During the advanced pretreatmen, PAC was selected as flocculant during flocculation and the dosage of PAC was 100 mg/L and the optimal pH value for flocculation was 7.0. During the catalytic oxidation reaction, the dosage of ozone was 30 mg/L and the reaction time was 30 min. The water quality of incoming membrane met the design requirements and the fouling of membrane system and cleaning frequency were reduced after advanced pretreatment. The membrane unit adopted a unique membrane system working mode and was equipped with a self-adjusting energy recovery device, which significantly reduced the energy consumption during membrane operation. It also can reduced the reverse osmosis concentration polarization phenomenon. During the operation of the project, the total electricity consumption per ton of water in the membrane unit was 1.38~1.40 kw∙h.