The Process and Water Quality Specialists

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Membrane Fouling

Membrane filters are porous membranes that separate particle and colloids larger than the membrane pore size using size exclusion.  This separation occurs by driving wastewater through the membrane fibers with pressure.  The rejected solids are retained on the membrane feed side, while particle reduced water passes through the membrane as filtrate.  Periodically, on a typical frequency of minutes, the MF system will undergo a backwash cycle where the rejected solids are scoured off the membrane surface with optional chemical addition to maintain productivity. However, MF systems also require chemical cleans (typical frequency is monthly) to restore membrane permeability and improve production at lower pressure. These are often referred to as maintenance cleans (lower chemical concentration for ~1 hour) and recovery cleans (higher chemical concentrations for longer duration). Although membrane fouling can be caused by organic and inorganic components, the most prevalent cause of fouling through out all membrane facilities is organic in nature.

In summary, it is important to work with a process engineer that understands filtration processes to make an appropriate selection for a given application. With the GMF process, we can develop a robust design to achieve water quality criteria, optimize and assist with an operating facility to achieve water quality objectives that are not being met, or expand an existing facility by testing and demonstrating that this can be safely done to the Department of Health. With regards to membrane filtration, not only is Trussell Technologies, Inc. familiar with the membrane products and equipment, but we also understand membrane fouling and the causes of membrane fouling. Membrane fouling can be caused by excessive flux rates or inadequate pretreatment, but it can also be caused by the application of inappropriate configuration or an over simplified approach to equipment procurement.