Filtration is a process used ffor the separation of solids from liquids, filtration process is used in which they are suspended. The aim is the recovery of filtered liquid and solids in form of cake or sometimes both. The average grade of dewatering is profoundly higher with the membrane filtration technique compared to the conventional technique with chamber filter plates. This filtration process is carried out by following way: filtration of a solid liquid suspension is carried out under pressure in a closed container system provided with chamber plates wrapped in the filter cloth into which the suspension is normally pumped. The working pressure chosen according to the specific needs normally ranges between 2-16 bars. The entire assembly is kept leak to that of the maximum feed pressure or membrane squeeze pressure. The significant advantage of the membrane filter plate technique is that the filtration phase is conducted only in the efficient area. The unproductive phase of pressure filtration, where the flow rates are already greatly reduced is replaced by squeezing with membrane which . This shortens the filtration cycle time considerably. Due to shorter cycles or increasing solid cake content of up to 50%, the filtration efficiency almost doubles. During squeezing the porosity of the filter cake decreases notably, so that additional de-watering occurs. With conventional pressure filtration the cake next to the cloth is dryer than in the centre due to the slope of pressure drop in the filter cake. The membrane causes a more even spread of the pressure so that homogeneous porosity is created within the cake. The average grade of dewatering is profoundly higher with the membrane filtration technique compared to the conventional technique with chamber filter plates. Due to shorter cycles or increasing solid cake content of up to 50%, the filtration efficiency almost doubles.
