PVC超滤膜处理生活污水及膜污染控制研究

发布时间：2018-01-16 17:26

本文关键词：PVC超滤膜处理生活污水及膜污染控制研究　出处：《海南师范大学》2015年硕士论文　论文类型：学位论文

【摘要】：膜分离过程是一种物理过程,具有选择性好,适应性强,节能等特点。在水处理行业中,超滤膜具有出水水质好的优点,但也容易由浓差极化和颗粒吸附等因素引起膜污染,因而超滤膜目前主要用于水的深度净化,尚未在实际污水处理领域得到推广应用。如何高效控制膜污染是超滤膜技术应用的重点和难点。本研究中选择了成本较低,制备容易,机械性能较好的PVC超滤膜,研究了PVC超滤膜处理生活污水的能力,采用脉冲进料的方式控制膜污染;运用计算流体力学,对脉冲进料影响膜通量的原因进行了模拟分析。1、PAC/UF处理生活污水实验考察活性炭PAC/UF处理生活污水的能力。比较了PVC直接处理和PAC/UF处理污水时的效果。结果表明:PAC/UF和UF过程对浊度的去除率都大于90%,但是投加PAC后,超滤膜的出水浊度稳定在0.1NTU以下;PAC表现出对有机物良好的吸附效果,PAC/UF过程对CODcr和DOC的去除率分别达到了45.4%和56%,与UF过程相比,分别提高了27%和35%。2、PVC分级处理生活污水及脉冲流控制膜污染实验研究为了研究PVC超滤膜直接处理高浓度污水的能力,实验将PVC超滤膜采用错流过滤直接处理某污水处理厂生活污水。结果表明:生活污水经三级过滤后,相关指标达到一级A排放标准,污水浊度降到0.1NTU以下;CODCr由120.97 mg/l降到47.34 mg/l,去除率为60.9%;DOC由8.95 mg/l降到4.08 mg/l,去除率为54.4%;细菌截留率为99.6%。其中二级处理时对CODcr、DOC的去除率最高,分别为35.2%和37.2%。超滤膜直接处理污水时,膜污染非常严重。因此,提出采用脉冲进料方式控制膜污染,主要考察了低频脉冲和高频脉冲两种方式对膜比通量J/J0的影响,结果表明脉冲频率越大,膜比通量越大。3、脉冲流强化超滤膜污染及计算流体力学模拟首先考察两种脉冲进料的方式:正弦脉冲SPF和间歇脉冲SPF对PVC超滤膜的膜通量的影响。实验表明:与稳定进料相比,在进料平均速度均为0.2 m/s时,SPF和IPF的渗透通量分别提高了45%和35%。以正弦脉冲为例,考察了脉冲强度和脉冲持续时间对膜通量的影响。实验表明:脉冲持续时间和脉冲强度都是影响膜通量的因素,但是脉冲持续时间起主导作用。当控制脉冲强度为0.2m/s,脉冲持续时间为30s时,膜通量出现了最大值。将计算流体力学CFD运用于中空纤维膜监测膜表面的剪切力变化和压力分布,模拟结果表明:采用脉冲进料的方式,膜表面的剪切力较高,沿着流体流动的方向下降的较慢;并且剪切力的变化受脉冲持续时间的影响较大。脉冲强度为0.1-0.2m/s,脉冲间隔为30 s时,压力降的消耗与稳定进料时压力降的值非常接近,是一种高效控制膜污染的方法。
[Abstract]:The membrane separation process is a physical process, has the advantages of good selectivity, strong adaptability, energy saving etc. in the water treatment industry, ultrafiltration membrane has the advantages of good water quality, but also easy to membrane fouling caused by concentration polarization and particle adsorption and other factors, so the ultrafiltration membrane is mainly used for water purification, get promotion not used in the actual sewage treatment field. How to efficiently control the membrane fouling is a key and difficult application of ultrafiltration technology. This study chose the low cost, easy preparation, good mechanical properties of PVC ultrafiltration membrane, study the ability of PVC ultrafiltration membrane for wastewater treatment, using pulse feeding method to control membrane fouling; computational fluid dynamics of pulse feed on membrane flux were analyzed.1, PAC/UF sewage treatment experimental study on sewage treatment capacity of activated carbon PAC/UF. Compared the PVC directly PAC/UF and sewage disposal effect. The results showed that PAC/UF and UF process on the removal rate of turbidity is greater than 90%, but after adding PAC, UF effluent turbidity stabilized below 0.1NTU; PAC showed good effect on the adsorption of organic matter, PAC/UF process of CODcr and DOC to remove 45.4% and 56% the rates were compared with UF process, were increased by 27% and 35%.2, PVC grade sewage treatment and pulse flow control of membrane fouling experiments in order to study the PVC UF treatment capacity of high concentration wastewater, experimental PVC ultrafiltration membrane by cross flow filtration, direct treatment of a sewage treatment plant sewage. The results showed that the three stage: sewage filter, related indicators have reached the level A emission standard, the sewage turbidity below 0.1NTU; CODCr decreased from 120.97 mg/l to 47.34 mg/l, the removal rate was 60.9%; DOC decreased from 8.95 mg/l to 4.08 mg/l, the removal rate was 54.4%; The bacterial retention rate of two 99.6%. of CODcr treatment, the highest removal rate of DOC, 35.2% and 37.2%. respectively UF wastewater treatment, membrane pollution is very serious. Therefore, the pulse feed control of membrane fouling, studied the influence of low frequency and high frequency pulse two ways of film bitung the amount of J/J0, the result shows that the pulse frequency is larger than the membrane flux,.3, pulse flow enhancing ultrafiltration membrane fouling and computational fluid dynamics simulation is first investigated two kinds of pulse feed way: sine pulse SPF and intermittent pulse flux of SPF of PVC ultrafiltration membrane. The experimental results show that compared with stable feeding in the feed, the average speed was 0.2 m/s, SPF and IPF flux were increased by 45% and 35%. by sinusoidal pulse as an example, the effects of pulse intensity and pulse duration on the membrane flux. The experimental results show that the pulse duration and The pulse intensity are the factors affecting the membrane flux, but the pulse duration plays a leading role. When the control pulse intensity is 0.2m/s, the pulse duration is 30s, the maximum flux. The computational fluid dynamics CFD applied shear stress surface of hollow fiber membrane monitoring membrane change and pressure distribution, the simulation results show that the by way of pulse feed, the membrane surface with high shear stress, decreased along the flow direction of the fluid is slower; and change of shear stress is greatly affected by the pulse duration. 0.1-0.2m/s pulse intensity, pulse interval is 30 s, consumption and stable pressure drop when the feed pressure drop values are very close that is a highly effective method to control membrane fouling.

【学位授予单位】：海南师范大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X799.3;TQ028.8

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