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_:—lX.�LO� The XIGAT"" Concept and Operation Manual Process Description The introduction of micro-and ultrafiltration as a large-scale filtration process was enabled by the development of highly resistant membranes and very much stimulated by the application of the crossflow concept, which had already been used in some ultrafiltration applications. The crossflow effect definitely enhanced the performance of ultra-and microfiltration processes. However, one major disadvantage did hinder the breakthrough for these filtration processes in large-scale applications: high energy consumption. The XFlow XIGATM-concept introduces the possibility to operate micro-and ultrafiltration processes in a dead-end mode. In this process, the energy consumption is a fraction of the energy consumption in crossflow processes. For this process, X Flow developed a novel membrane filtration element, using permanently hydrophilic capillary membranes. The element design is based on a 8"construction also known from the spiral-wound technology, typically used within the RO industry. A standard pressure vessel fitted with several elements, can be fed from one side, but also from both sides. An advantage of the latter process mode is the low pressure drop, so that a constant production over the entire length of the vessel can be achieved. Typically, the process is operated with a constant permeate flow. Consequently, the transmembrane pressure (TMP)will increase during filtration. A periodical backflush process using permeate is required to control the increase of TMP. Periodically dosing of disinfectants like peroxide or hypochlorite is recommended, in order to control bacterial growth and -consequently-TMP increase. In addition, e.g. a monthly cleaning using chemicals like sodium hydroxide, EDTA, citric acid etc. may be used. i Large scale membrane filtration plant at PWN/The Netherlands according to XIGATM -Concept CAPF-XIGA-0143