The implementation of a membrane filtration system for wastewater treatment has been largely adopted by industries since the last few decades. And the reason behind this rise in implementation would be the high purification results delivered by the membrane systems. Whether it’s for purifying potable drinking water (commercial use) or treatment of wastewater from industries (industrial use), membrane systems today have become a necessity for both sectors. Wastewater is treated by four different membrane filtration techniques:
microfiltration, ultrafiltration, reverse osmosis and nanofiltration and these systems are used based on the level of water quality needed. These systems are even combined in the industry sector sometimes to treat the wastewater more effectively.
Moreover, membrane systems are huge and important investments – be it on the professional or personal front and it becomes important to protect the investment at least for the time period that is possible. One of the main aspects that affect the performance of any membrane system is its “cleaning”. Yes, it might seem like a not so important
aspect, but it is, as this would not only decide the performance level but even the life expectancy of it.
When wastewater or water, in general, is treated with membrane systems, what happens is that the salts and the impurities get accumulated on the surface of the system. The deposition of the salts is termed as fouling or scaling in terms of membrane filtration systems. These deposits when not cleaned for a long time can adversely affect the functioning of the membrane system. Before the wastewater or a solvent is passed through a membrane, it can be pretreated so as to decrease the accumulation of these waste material on the membrane surface. Pretreatment methods generally involve chemical pretreatment of water or cartridge filtration.
Well, having knowledge about the pretreatment methods as well as implementing is vital, but this should be backed by the cleaning of the membranes. Effective functioning of a membrane system is possible when you the “when” of its cleaning i.e. the frequency. You know you need to clean the membranes, but the question is how often. This where monitoring becomes important. You need to monitor your membrane filtration system in order to decide upon the frequency of cleaning. You need to collect as well as monitor the daily operational data so that you can carry out the cleaning on a frequent basis. The maintenance and cleaning of the systems should be performed to enhance the operational aspect not just for ticking off the cleaning aspect off the list.
Besides the frequency of cleaning, one other thing that plays an important role in the pretreatment is the type of cleaners used. In general, two types of membrane cleaners are used – high and low pH solutions. The high pH cleaning solutions are best for cleaning the organic suspended solids, microorganisms, colloids, etc., in short, the
heavier stuff. And the low pH cleaning solutions are best used for dissolving accumulation of oxides and metal components. Well, it really depends on the level of fouling your membrane system has and based on that you can determine the type of cleaner for cleaning your system.
Hence, once you determine the frequency as well as the type of cleaners best suited for your system, you can then keep track of the whole cleaning aspect of yourmembrane filtration system.