Microfiltration advantages

This technology removes dissolved metals from liquid wastes at a lower cost then other treatment options, such as precipitation followed by clarification and conventional filtration, ion exchange, reverse osmosis, and electrolysis. An advantage of the DuPont/Oberlin microfiltration technology is that it produces a dry, stabilized cake that can be landfiUed when used in conjunction with a filter aid/cake stabilizing agent. 

According to the vendor, the EPOC microfiltration technology offers several advantages ... 

The liquid waste must be pumpable. Contaminants must be in particulate form, or it must be possible to precipitate dissolved contaminants such as metal ions chemically. Separation must provide an advantage. The EPOC microfiltration technology does not remove volatile organic compounds (VOCs) from liquids. The unit s operation is affected by cold weather. 

The cells and cell lysates (fragments of disrupted cells) can be separated from the soluble components by using microfiltration (Chapter 8) with membranes. This separation method offers following advantages ... 

Microfiltration can be used to replace a clarifier in the chemical clarification of plating discharges. Compared to conventional equipment, it offers the advantages of continuous processing and significantly smaller space requirements. Figure Nine (9) illustrates a microfiltration installation. 

The advantages and disadvantages of in-line microfiltration and cross-flow filtration are compared in Table 7.2. In general, in-line filtration is preferred as a polishing operation for already clean solutions, for example, to sterilize water... 

Table 7.2 Comparison of advantages and disadvantages of in-line and cross-flow microfiltration...

Microfiltration is widely used for the removal of cells and fragments from suspension. It is also used as a method of sterilization of solutions, and has the advantage of high efficiency, simplicity, compactness, and reliability. 

A practically useful predictive method must provide quantitative process prediction from accessible physical property data. Such a method should be physically realistic and require a minimum number of assumptions. A method which is firmly based on the physics of the separation is likely to have the widest applicability. It is also an advantage if such a method does not involve mathematics which is tedious, complicated or difficult to follow. For the pressure driven processes of microfiltration, ultrafiltration and nanofiltration, such methods must be based on the microhydrodynamics and interfacial events occurring at the membrane surface and inside the membrane. This immediately points to the requirement for understanding the colloid science of such processes. Any such method must account properly for the electrostatic, dispersion, hydration and entropic interactions occurring between the solutes being separated and between such solutes and the membrane. 

Table 16.3 Advantages and limitation of various module configurations for microfiltration and ultrafiltration membranes.

Microfiltration as pretreatment to RO is used for bulk removal of suspended solids and bacteria. Microfiltration is a barrier technology that can in many cases replace conventional clarification and filtration. Advantages of MF over conventional clarification and filtration include the following ... 

Microfiltration units can be configured as plate and frame flat sheet equipment, hollow fiber bundles, or spiral wound modules. The membranes are typically made of synthetic polymers such as Polyethersulfone (PES), Polyamide, Polypropylene, or cellulosic mats. Alternate materials include ceramics, stainless steel, and carbon. Each of these come with its own set of advantages and disadvantages. For instance, ceramic membranes are often recommended for the filtration of larger particles such as cells because of the wider lumen of the channels. However, it has been shown that spiral wound units can also be used for this purpose, provided appropriate spacers are used. 

Microfiltration using glass fiber filter disks is an efficient alternative to centrifugation for the separation of free antigen from antigen-antibody complexes. When small numbers of samples are involved in manual methods or for mechanized aparatus, microfiltration has advantages over centrifugation. 

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