- 16 November 2006 -

New UF module can decrease footprint

A novel ultra filtration (UF) module intended mainly for water treatment, biotechnology and beverage filtration has recently applied for patent. According to its creator, Hardy Lapot of FluxConsult, the ideas contained in the application literature "will open a new chapter in the development of membrane filtration".

"All currently available modules - whether of the hard outer shell or of the submerged type - have distinct disadvantages, which the industry seems up till now to have accepted," Lapot says. These disadvantages are the large footprint created by hard outer shell module systems and the unused head space for the removal of modules in submerged systems; in unequal flow patterns either on the permeate or on the retentate side; and in stress and fatigue effects on individual fibres, he explains.

Other current problems in UF modules include fouling due to uneven TMP along the length of a fibre resulting in different flux rates, problematic cleaning and sanitization. It [is also difficult or even impossible to reverse flow or back flush. Many of these problems can be also attributed to compaction of fibres creating dead zone on the permeate and/or on the retentate side.

According to its creator, the newly-invented UF module does away with such disadvantages. It is based on the state of the art concept of horizontal layers of equally spaced fibres, where one layer is put on top of another at an angle and so on. In the new module, some layers consist of so-called injection tubules. A stack of fibre respectively tubule layers is potted in at all four sides, resulting in a module frame. The fibres are open ended on three sides of the frame, and the injection tubules on the fourth. Any liquid to be filtered or air to be scoured can be pumped directly into the fibre layer stack, inside the potted frame through the injection tubules, causing turbulences. If desired, cross flow velocity can be created by pumping liquid through the inside of the potted frame and the stack of layers, Lapot says.

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