OSN Membrane Q&A

What is Membrane Nano Filtration?

According to Wikipedia OSN is “a membrane filtration-based method that uses nanometer-sized through-pores that pass through the membrane. Nanofiltration membranes have pore sizes from 1-10 nanometers, smaller than that used in microfiltration and ultrafiltration, but just larger than that in reverse osmosis. Membranes used are predominantly created from polymer thin films.”


How does it apply to Botanicals?

OSN can be used for solvent recovery (Desolvation). OSN is essentially an FFE/WFE/Roto killer. It eliminates the need for one of these systems except perhaps on the very largest of operations.

It can be used for in-line, continuous “winterization” at ambient temperature. In this application, “Winterization” is a misnomer since OSN can remove not only lipids, fats, and waxes, but also degums and removes phosphatides and phospholipids. It also removes some chlorophyll and carotenoids and removes sugars and water-soluble compounds. We refer to these membranes as “Remediation” membranes since it more accurately describes the function.

OSN Membranes can also do Terpene isolation, doing so delicately without thermal degradation. This process is much more gentle than steam distillation or stripping terpenes from crude via other thermal methods.


Can your machines perform remediation and desolvation simultaneously?

No. Functions are dependent on the type of membrane element used. Therefore, it can only perform one function at a time. Some of our equipment offers functions that allow switching between alternate housings which contain different types of elements. This allows switching applications without opening housings and replacing elements.


Is it practical to swap membranes daily for desolvation and remediation on the same machine?

No. It is not recommended due to the possibility of membrane damage. 2.5” housings are very challenging to open, and the operation is cumbersome. 4" and 8” housings are less complicated to open. If necessary, elements can be swapped though we don’t encourage it. We can offer systems that have 2 sets of housings that allow duplex functions.


What is the life expectancy of Membrane Modules?

The life of elements varies based on care, usage, and application. Manufacturers currently do not have data to support any claims on membrane life. Customers report life spans of 9+ months and counting. It is realistic to expect life spans of 6-18 months.


How is it possible that membranes last such a long time?

Membrane elements work on a different principle than other filtration methods such as filter paper or lenticular modules which are classified as "dead end" filtration. Membrane elements work on a “Tangential” flow where there is a strong current of fluid moving across the membrane surface (crossflow) as well as some molecules permeating through the membrane. When a particle clogs to the membrane surface, the crossflow dislodges those particles and cleans that pore. Thus, these elements are self-cleaning and provide long element life.


Can I use any brand of Membranes?

Yes. Most commercial elements are compatible, or an adapter can be obtained to work with the membranes. There are a few companies that make elements with proprietary adapters but in general, most membranes are compatible. It is important to note that you have the freedom to use elements from other manufacturers, as eventually more companies will introduce specialized membranes that perform better than the current technology. More than likely you will be able to upgrade your system by switching to those membranes without changing systems.


Is pre-processing required before using Membrane Filters?

Yes. Pre-filtration of the miscella stream is necessary to avoid fouling or scratching the membrane surface.


What equipment is recommended for pre-processing?

Any filter capable of filtering down to 10 microns is acceptable, though we typically prefer a Candle Filter or a Filter Press.


What solvents can I recover? What is the chemical compatibility of these systems?

Most solvents are compatible since we typically supply systems with Viton O-Rings. Elements chosen will depend on the chemicals used. There are elements compatible with Ethanol, Methanol, Isopropanol, Pentane, Hexane and Heptane, and others.


What percentage of solvent is recovered from my miscella feed stream?

Typically, about 90% of the solvent is recovered. That rate can be adjusted depending on user requirements.


Can I remove water from my solvent (Reproofing)?

No. Other membrane technology is required for this process and is completely different from OSN.


Does filtration occur in series or tandem?

Filtration occurs in series where housing one feeds housing 2 then 3 and 4. Each housing causes a pressure drop so you are limited by the number of housings you can have in series. Typically, we use 4 housings in series.


Explain the different sizes of membranes?

Membranes are classified by diameter and length. A 2540 membrane is 2.5” in diameter (pretty much) and 40” long. There also are 4” and 8” membranes, different lengths, and elements vary in diameter but are roughly the diameter necessary to fit in the housing though some exceptions exist.


What are the flow rates for solvent recovery or remediation?

A 2.5” membrane can currently remediate or winterize 30 gallons per hour in series of 4 housings. 4” elements can do 90 GPH and 8” can do 400 GPH. As new elements are tested, we will find elements with better throughput.

Currently solvent recovery on a 2.5" system is 90-120 GPH in ethanol and even greater in Methanol.


Are these units safe, and are they ASME certified and peer-reviewed?

Yes, these units are safe. They have been Peer-Reviewed, have electrical connections that are “Intrinsically Safe.” 2.5” and 4” housings are not rated by ASME as pressure vessels, but 8” housings that we do use are ASME stamped.


What do the “Remediation” membranes remove?

They remove lipids, fats, waxes, chlorophyll and carotenoids, gums, phosphatides, phospholipids, some water-soluble compounds, and sugars. Currently, 95+% of fats can be removed at room temperature. Other compounds vary in remediation efficiency.


Can remediation membranes remove THC from CBD?



What percentage of fats are removed from my miscella feed stream?

Currently, we can remove 95+%.


Do you have membranes for sugar removal.

Yes. We can effectively remove 90%+ of sugars from crude with sugar specific membranes.


What is the loss in cannabinoids associated with the remediation process?

Negligible if post-processing is done. The remediation process will remove contaminants at a 2:1 ratio typically. In a 1,000-gallon miscella stream with 5% fats and other contaminants that get removed in the remediation process, you would remove 150 gallons from the original stream. 100 of these gallons is your miscella. If the total cannabinoid concentration of the solution was 5%, you would thus have 5 gallons of viable crude to recover from those 100 gallons of miscella.


How can I recover those losses?

We recommend winterization at -20F. This can be done overnight in a normal freezer or continously if re-run through the OSN. Typically, this would be reprocessed when there are sufficient fats to process. Normal filtration will efficiently separate all fats and the clean miscella can continue down your normal process line or be diluted to 10:1 and reprocessed in the OSN. We recommend fats be removed ideally in a candle filter or a filter press, or a Buchner trolley for smaller batches.

If you have spare OSN capacity, a second alternative is to dilute the solution to 20:1 and reprocess with OSN. Once reprocessed, this reduces the potential losses to 0.25 gallons or 0.5% more or less. The residual solvent can be recovered through evaporation or OSN.


Is refrigeration required in the remediation process?

No, however research suggests that certain lipids with small molecules can be removed when agglomerated by reducing the solution temperature. This may sound like traditional winterization but does not require as much time nor such deep temperatures to achieve great results. Reducing the solution’s temperature also has the benefit that it increases the removal of other contaminants, especially chlorophyll. The use of Methanol also greatly improves the filtration process and can be accomplished at warmer temperatures.


What dissolution ratio can I feed the machine for the remediation process?

We typically prefer 4:1 but you can experiment to find a more efficient ratio.


What solvents should I use for remediation?

If you are using a particular solvent for extraction, it does not make sense to change solvents, so we recommend you use your extraction solvent for remediation. If you have BHO or CO2 crude and need to dissolve in a solvent, methanol works better. Methanol has a Hildebrand Solubility Parameter of 36.2 while ethanol is 26.2. This makes waxes, with a Hildebrand Solubility Parameter of 16.36 less soluble in methanol than ethanol and thus easier to fractionate out. We encourage you to test different solvents and share with the broader community your results.


Can I extract at room temperature and remediate with Membrane Technology?

Absolutely! We believe OSN technology allows the elimination of ultra-low extraction temperature since remediation does a great job of removing those contaminants. It is most cost-effective to remediate using OSN than to avoid the contaminants in the first place by using cryo extraction temperatures.


How much power do these machines use?

This varies by manufacturer, but the most efficient systems are as follows:

2.5” System: 4.2 amps if 3-phase 460v or 15 amps if single-phase 230v

4” System: 14.8 amps, 3-phase 460v

8” System: 30.4 amps, 3-phase 460v


What is the ideal batch size for each system?

This varies by manufacturer but in general, we recommend the following based on housing diameter and systems configured with 4 housings. This gives you an idea of where the cutoff is so you can determine what systems is best for you.

4x 2.5” Housings: 25 gallons

4x 4” Housings: 75 gallons

4x 8” Housings: 250 gallons


How does the Terpene Isolation process work?

Terpene isolation is achieved by using “loose” membranes that allow terpenes to permeate along with the solvent. This method is far gentler than separation of terpenes than using steam distillation. If using BHO/PHO as an extraction method, OSN will ensure those volatile terpenes are better preserved. Typically this process is done with a solvent such as Pentane since the solvent can be stripped from the terpenes at room temperature under vacuum.


Why choose SC Filtration over other manufacturers?

SC Filtration is a distributor of Membrane Filtration systems. We have no vested interest in whatever manufacturer you choose. We give you unbiased advice and options to choose from based on your specific needs. SCF stocks equipment to avoid extensive manufacturing lead times, and we offer the same prices or lower than purchasing directly from a manufacturer.