Water Treatment by Submerged Membrane Separation in Sedimentation Tank with Powdered Activated Carbon Dosage

本研究以微滤膜组件浸没于沉淀池中，开发饮用水处理系统。为研究粉末活性炭（PAC）对膜分离的影响，采用磁力搅拌器驱动的小型膜组件进行恒压过滤实验，考察了PAC对膜分离的影响.原水是被处理过的污水污染的河水。测试了添加PAC或不添加PAC的不同压力组。通过反冲洗和化学清洗的方法考察了膜系统的可行性，投加PAC对膜分离没有影响，反而延缓了膜的堵塞。添加PAC的膜阻力增加速率明显小于未添加PAC的膜阻力增加速率，过滤压力较高的膜阻力大于压力较低的膜阻力。高压模块和低压模块之间的通量相差不大。当给水中曝气时，悬浮物不沉降，阻力减小;当施加较高的过滤压力时，膜和表面堆积层被压缩，阻力增大。这意味着较低的过滤压力延长了膜的堵塞，并在化学洗涤之间的过滤循环期间产生更多的水。高悬浮固体浓度的PAC或比阻力小的淤泥不会影响过滤，而是防止增加阻力的细颗粒的积累。证实了PAC在膜分离中应用的可行性。

The researcher developed potable water treatment system by micro-filtration membrane modules submerged in sedimentation tanks. The system can stand for heavy suspended solid lording during a flood, however it can not remove dissolved organic substances such as bad taste and odor.Powdered Activated Carbon (PAC) can be added to remove organic substances, but it may disturb membrane separation.To investigate the effect of PAC on membrane separation, constant pressure filtration experiments were conducted using small membrane modules that were driven by a magnetic stirrer. The raw water was river water polluted by treated sewage. Different sets of pressure with PAC addition or without PAC were tested. Back-washing and chemical washing were also applied to determine feasibility of the membrane system.Addition of PAC did not disturb membrane separation at all and it rather delayd clogging of membrane. Increase rate of resistance of membrane with PAC was apparently smaller than that of without PAC.Resistance of membranes of higher filtration pressure was larger than that of lower pressure modules. There was not much difference of flux between the high pressure modules and the lower pressure ones. When the feed water was aerated and suspended solid was kept from settled, the resistance decreased.The membrane and accumulated layr on the surface were compressed and the resistance increased, when high filtration pressure was applied. This means that lower filtration pressure extends clogging membrane and produces more water during a filtration cycle between chemical washings. The high suspended solid concentration of PAC or silt of which specific resistance is small will not affect filtration and rather prevents accumulation of fine particles that increase resistance. The feasibility of applying PAC at membrane separation was confirmed.