【作者】 刘纳；

【导师】 黄健平；

【作者基本信息】 华北水利水电学院 ， 环境工程， 2011， 硕士

【摘要】 膜法水处理技术是一种新型的污水处理技术。在水资源缺乏和水污染日益严重的今天,该技术显示出强大的生命力而倍受青睐,成为废水处理与资源化的关键技术之一。本论文将自制的新型超滤平板膜和五孔中空纤维膜组件应用于城市污水处理,考察其处理效果、膜污染和再生性能。主要结果如下:(1)采用污水处理厂二沉池出水作为超滤膜的进水,研究以超分子β-CD为添加剂制备的PVDF/PMMA、PES超滤平板膜及商品PES平板膜的处理效果、污染性能和再生方法。结果表明平板膜的出水均比较稳定,达到了回用水的水质要求。PES商品膜和PES膜的运行初期膜通量下降较快,后期逐渐趋于稳定;以1.5h为界限,把过滤过程分为两个阶段,第?阶段符合膜孔堵塞模型,第Π阶段符合沉积层阻力模型; PES商品膜、PES膜清洗的结果表明在本实验中反冲洗效果较差,H2O2浸泡效果良好。清洗后膜的通量恢复率均在90%以上,膜的再生性能良好。相比之下PVDF共混膜的通量一直处于较稳定状态,运行时间超出PES膜约5倍时仍不需要清洗,表明改性后的PVDF膜亲水性良好,膜污染较轻。(2)采用自制的两种不同共混材料PVDF膜(PVDF/PMMA/TPU膜(膜组件A)和PVDF/PMMA/PVC膜(膜组件B)),系统研究了膜处理城市污水的处理效果、膜污染性能和膜清洗特性。实验结果表明膜组件的出水水质参数均达到了《城市污水再生利用城市杂用水水质》(GB/T18920-2002)的要求。与传统处理工艺相比,省略了后续的混凝沉淀、砂滤、消毒工艺,彻底消除氯消毒产生的氯前驱物造成的危害。对膜污染控制研究,得出连续运行的方式膜污染最严重;间歇运行方式的较佳抽停比为10min∶2min,延长抽停比可加剧膜污染,抽-反冲运行方式膜污染速率最小。PVDF/PMMA/TPU共混改性膜对污染物的去除率比PVDF/PMMA/PVC共混改性膜的去除率稍高。实验表明PVDF/PMMA/TPU共混体系和PVDF/PMMA/PVC共混体系制备的五孔中空纤维膜具有优良的性能。通过膜阻力分析得出膜阻力主要为可逆阻力(浓差极化边界阻力),可通过物理清洗的方法得到去除;其次为纯膜阻力;不可逆阻力(膜污染阻力)所占比例最小;说明两种共混膜的抗污染性能较好。通过进一步的研究,得出高速水力冲洗+NaClO溶液浸泡是一种有效且省时的清洗方法。后续的研究也证实这种方法的有效性,膜通量恢复率达到90%以上。与膜组件B相比,膜组件A具有更好的抗污染性能,膜组件A运行周期是膜组件B运行周期的2倍以上。综上所述,PVDF共混改性膜在城市污水处理中具有一定的应用前景,新型超滤膜水处理性能的研究结果为新型耐污染水处理膜的应用提供参考。更多还原

【Abstract】 Membrane process is a novel wastewater treatment technology. This technology has rapid development and a wide concern because of water resource deficiency and water quality deterioration. Membrane process has been used as a key technology for water reclamation and reuse of water resource. In this dissertation, the membranes were used to treat municipal wastewater, and the effluent quality, membrane fouling and cleaning properties were studied. As a result, the following conclusions were drawn:(1) The membranes were used to treat the effluent from sedimentary tank of municipal wastewater treatment plant. The wastewater treatment performance, fouling characteristics and regeneration characteristics of PVDF/PMMA-β-CD, PES-β-CD composite plat ultrafiltration membranes and PES plat commercial membrane were investigated in comparable conditions. The results showed that the effluent can meet the demands of water reclamation. The flux decreased ratios of PES commercial membrane and PES membrane were high during the initial period and tended to stably during the later period. Took the 1.5h for the boundary, the filtration period was divided into two periods. Period ? was fit to the standard blocking filtration model and periodΠwas fit to cake filtration model. The results obtained by cleaning methods of PES commercial membrane and PES membrane showed that backwash has little effect on membrane permeability recovery, and H2O2 soaking is effective to recover membrane permeability. Compared with PES commercial membrane and PES membrane, the flux of PVDF membrane was in a stable state, the operating time of PVDF membrane was six times as much as that of PES membranes and PVDF membrane didn’t need membrane cleaning. The results showed that the hydrophilicity of the modified PVDF membrane was excellent and membrane fouling was slightly.(2) Two different types of composite fivebore hollow fiber membrane modules which are module A (PVDF/PMMA/TPU blends) and module B (PVDF/PMMA/PVC blends) in presence of the same biomass concentration were applied to verify the effluent quality, fouling characteristics for domestic wastewater treatment. All the results of the experiments were complied with standard of the effluent discharge standards to urban miscellaneous water consumption (Reuse of recycling water for urban-Water quality standard for urban miscellaneous water consumption) (GB/T18920-2002). The system produced effluents equivalent to those of an oxidized, coagulated, clarified, filtered, and disinfection wastewater and could reduce following tertiary treatment process, endanger of chlorine precursor was completely eliminated. The method of mitigating membrane fouling was studied. The result showed that the more severe fouling happened during the constant condition. The optimum operation condition of intermittent filtration condition of suction time/suspended time ratio was 10min/2min, membrane fouling increased as suction time/suspended time ratio increased, membrane fouling rate reached lowest during suction-backwashing condition. The PVDF/PMMA/TPU blends did a little better than the PVDF/PMMA/PVC blends in terms of removal efficiencies. The results showed that PVDF/PMMA/TPU blends and PVDF/PMMA/PVC blends posses excellent characteristics.The result of fouling resistances propensity showed that the reversible fouling resistances, which was produced by concentration polarization and can be removed by physical cleaning, was the main membrane resistance, then was the intrinsic membrane resistance, and the resistance caused by solute adsorption into the membrane pores and wall was the least. The anti-fouling characteristics of membranes were excellent. By measuring the flux of membrane and cleaning membrane module of different methods, it was founded that wash out by water and soaking in NaClO solution was effective in control blend membrane module pollution. The latter study also verify the conclusion and the membrane flux recoveries were over than 90%. Compared with the module B, the module A had better anti-fouling characteristics, the operating time of module A was twice as much as that of module B.In conclusion, the modified PVDF blend membranes would be well applied in the future. The research studied on wastewater treatment performance and membrane fouling of novel ultrafiltration membranes would provide a reference basis for the application of novel anti-fouling ultrafiltration membranes on wastewater treatment.更多还原