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VSEP’s Membrane Technology

Written on February 3, 2015

VSEP systems use membranes which are made from various thin film composites and polymers such as polyether sulfone and polyamide.  There are over 200 different membrane types being used throughout the VSEP systems.

New advances in membrane technology have led to increased capabilities in filtration techniques, especially to do with applications involving wastewater and other environments involving processing harsh water products.  For example; there are nano-filtration membranes being implemented that are able to withstand extreme temperatures and pH ranges.

New Logic Research’s VSEP modules come in a variety of sizes and configurations. The membranes are attached to a steel tray and stacked in an array, much like a traditional plate and frame configuration.

Membranes are films that allow smaller objects to pass through while rejecting the larger ones. So, any supply stream flowing through a membrane system such as a VSEP will be split into two. The cleaner stream with fewer objects is known as the permeate and the dirtier stream with higher solid particle density is called the concentrate.

Depending on the application and what the required output is, the concentrate can either be the desirable material (in product recovery), or it can be unwanted (wastewater treatment).

There are four basic categories of membranes used and characterized as followed:

Micro-filtration (0.1µ – 2.0µ)

Are made from PTFE (Teflon®) and are used to remove small suspended solids, large colloidal material, some emulsions and most bacteria.  They are unable to filter out any dissolved solids. The membranes are useful for dewatering slurries such as titanium dioxide and calcium carbonate.

The Teflon membrane are the most durable of all membranes used in VSEP modules and can withstand temperatures up to 130 degrees, pressure between 200-690 kPa and a pH range from 0-14.

Ultra-filtration (0.008µ – 0.1µ)

These membranes are used in most applications where filtration is required to only filter out all suspended solids.  They will remove large organics such as proteins, pyrogens, bacteria and colloids and can break emulsions without the need for chemicals.

Ultra-filtraton can be used as the primary treatment where incredibly dirty wastewater is being recycled using a secondary reverse osmosis membrane system. The ultra-filtration membranes are made from PVBDF (Kynar®) and generated cellulose. The membrane operates between 200 and 1,720 kPa, temperatures up to 90 degrees and a pH range of 1-14.

Nano-filtration (0.001µ – 0.01µ)

This is the newest membrane produced by New Logic Research in VSEP modules. They are semi permeable and made from materials such as sulfonated sulfone, polyamides and other thin film composites. They are usually used to remove organics and many dissolved materials such as hardness and are seen implemented in wastewater treatment to remove Biological Oxygen Demand (BOD).

Nano-filtration systems can be used as a pre-treatment for a reverse osmosis system or spiral RO system.  The system can operate at pressures from 1,380-4,130 kPa and withstand a pH range from 1-14

Reverse Osmosis (30 daltons – 0.001µ)

It is the finest filtration system available from New Logic Research and it has the ability to filter dissolved solids such as sodium chloride. Due to its capabilities, it is used in applications involving desalination plants for seawater and is able to reject 99.5% Na-Cl.

RO membranes are often used to remove organics, trace oil and trace metals in a single cycle process. RO membranes have not been considered effective in an industrial application due to high probabilities with fouling, but VSEP’s vibrational feature reduces the risk of fouling. This has enabled membrane technology to be useful with filtration applications where removal of low molecular weight contaminants from a wastewater stream is desired.

RO membranes are more or less constructed of propriety thin film composites.  These membranes operate at 2,070 – 6,900 kPa and can tolerate a pH range of 2-12.

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