How Is an M.W. Watermark™ Filter Press Used in the CBD Extraction/Purification Process?


Filter presses have been used to separate solids from liquids for hundreds of years in hundreds of markets. In the past few years, processors of CBD (cannabidiol) have learned to use filter presses in a variety of steps in this process.

M.W. Watermark Pro-X 630 with Precoat Skid on-site with a filter cake in a dumpster

Below is a brief overview of the steps in which M.W. Watermark Pro-X™ filter presses have been used in the processing and purification of CBD.

Biomass/Solvent Separation – This is a very common application for a filter press. Dried hemp (the biomass) is ground and mixed with a liquid solvent, often ethanol. The biomass/solvent slurry is pumped through a filter press. The hemp stays in the filter press, and the solvent leaves the filter press as the filtrate, free of nearly all visible suspended solids.

Biomass filter cake close-up of someone holding it in their hand showing the inner details.
Biomass Filter Cake

Post Screw Press – Often a screw press is used to separate the hemp from the solvent. This also is an efficient process, but fine solids may be in the pressate (liquid leaving the screw press). This pressate may be pumped through a Pro-X filter press to generate a solvent/oil blend nearly free of suspended solids.

Post Centrifuge – Similar to the post screw press application discussed above, a filter press may be used to remove suspended solids from the centrate following a centrifuge.

Winterization – Filter presses have been used in the winterization step to “purify” edible oils such as sunflower oil and palm oil, for many years. At low temperature, waxes and other contaminants are solid and may be separated from the solvent that remains a liquid. This process is the same when trying to remove waxes from the solvent/crude oil mixture in the CBD process. The slurry at very low temperature is pumped through the Pro-X filter press, and the contaminants in the slurry remain in the filter press, while the filtrate leaving the filter press is free of the waxes and other contaminants. At low temperature, it may be necessary to use special filter plates, so be sure to communicate the intended winterization temperature to our experienced team at M.W. Watermark™. Note that some companies choose to filter the entire solvent/biomass slurry at low temperature thereby accomplishing the biomass separation and winterization in one step with a filter press.

Wax/Lipid Winterization filter cake held close-up by hand to show the clear separation of filter aid and cake.
Wax/Lipid Winterization Filter Cake
Winterization solution filtrate filling a stainless steel container.
Winterization Solution Filtrate

Chlorophyll and Color Removal – Some companies choose to remove chlorophyll or simply color during the CBD separation process, often by blending activated carbon with the liquid phase. A filter press also may be used to separate the activated carbon from the liquid phase in much the same manner as discussed above. Again, filter presses have historically been used to remove activated carbon in many other markets, often in the food and beverage sector.

Pro-X 470 stainless steel manifold and AOD pump on a shelf
Pro-X 470 Manifold and Pump

This is only a brief overview of the many steps in the CBD extraction and purification process where a Pro-X filter press may be used. Please contact M.W. Watermark for specific details related to your process.


About M.W. Watermark
M.W. WATERMARK wants to make a difference. We are passionate about the world’s water. We are innovative, focused on customer service and always try to exceed expectations. We are an environmentally conscious company with people who are energized, encouraged and inspired to make a difference on our planet by helping to keep our shared, finite water supply clean and usable for generations to come. We build amazing, custom water and wastewater treatment equipment. Together, we can make a difference.

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M.W. Watermark is a trademark owned by M.W. Watermark, L.L.C. All rights reserved.

How Is an M.W. Watermark™ Filter Press Used in the CBD Extraction/Purification Process?