Microfiltration Membrane System

Microfiltration is a type of membrane separation technology used in wastewater treatment plants which is developed to remove foreign particles that cause turbidity in water. It is often selected as an alternative method for achieving better water clarity and it is considered far better compared to conventional granular media filtration processes. Common systems are usually applied and built under concrete separation tanks with some advanced technology utilizing the smallest porous membrane that goes up to 0.2 micron.

The general principle on how the whole system works depend largely on the use of a vacuum pump to draw water across the filter and thus, particle size larger than the porous membrane will get trapped. And because the pore size is small enough to even capture common microorganisms, conventional wastewater treatment plant that is equipped with microfiltration technology will usually void the need to have additional chemical processes or ozone disinfection unit to kill harmful pathogens. Therefore although the initial start up cost may be higher than other unit of operations, it is actually more cost effective and economical in the long run and wastewater discharge coming out from the system can easily comply and adhere to any local government regulations since it can achieve disinfection without use of any chemicals.

Latest development to further increase the effectiveness of the microfiltration system has seen some modification been done to further enhanced its capability to even remove water soluble chemicals as well. Usually to achieve that, iron or alum is normally added with a certain percentage that functions as coagulant to precipitate and trap water soluble contaminants. Formation of layers of cake coagulant on the surface of the membrane not only helps to enhance filtration efficiency but also it can also improve membrane reusability normally by enhancing backflushing process capability.

Studies have also found that running microfiltration system in cross flow mode does not necessarily offer any significant advantage. Basically in a cross flow condition, water flow is moving tangentially over the surface of filtration membrane and although argument were leveled saying that this will limit thickness of the cake formation, in the long run however, overall efficiency is more or less similar as if the filtration is operating in normal mode.

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