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FREO2’s Oxygen “SIPHON” System


FREO2, a company in Australia, has discovered a new way to produce oxygen for intensive aquaculture operations.


In November 2015, FREO2 published a brief report on its “SIPHON” oxygen production system in the peer-reviewed journal Pneumonia.  The report contains information on how the system functions, the problems that it is designed to solve, and data from a prototype that’s operational in Gippsland, Australia.  There is also a section that describes the next steps in the development and implementation of the system.


In 2016, the FREO2 Foundation formed a partnership with Green Camel l, an aquaponics farm in Western Sydney that produces barramundi (a fish).  Kevin Rassool, who manages the partnership, says the FREO2’s “Siphon” system offers Green I Camel a cost-efficient and reliable alternative to the traditional oxygen supply option.


FREO2’s website says: The “Siphon” approach relies on exploiting the reduction in pressure of water flowing through a raised siphon to create a source of vacuum (see diagram below).  This is used to power a customized vacuum-pressure-swing-adsorption system and produce medical grade oxygen.


In 2017, Australia’s Fisheries Research and Development Corporation gave FREO2 a special award and described the Siphon system like this: By directing running water through a raised pipe, the Siphon creates a vacuum, which is the power source used to concentrate the atmospheric air into oxygen.  The vacuum squeezes’ air through a molecular sieve, effectively trapping all the nitrogen and removing it from the air.  The resultant gas is up to 95 percent pure oxygen.  It uses no electricity, and the only ongoing cost is replacement or refurbishment of the cheap molecular sieve after five to 10 years!


The journal Pneumonia described the system like this: These devices contain molecular zeolite sieves, made from an abundantly available, low-cost mineral.  When air is compressed and brought into contact with zeolite, nitrogen in the air is preferentially adsorbed over oxygen.  As the pressure is reduced, the trapped nitrogen can be released again.  A cyclic process, known as pressure-swing adsorption, can be used to remove nitrogen from the air in this way.  Concentrators typically combine two canisters of zeolite with an air compressor, tapping the oxygen from the canister under compression while venting the nitrogen from the other.  This cycling of compression and decompression creates a continuous flow of up to 95% pure oxygen.


Kevin Rassool, manager of aquaculture operations at FREO2, forwarded the following copy that provides some additional information on FREO2 and its plans:



Sources: 1. FISH (Australia’s Fisheries Research and Development Corporation News).  Oxygen Engineer Wins FRDC Award.  Tom Bicknell.  Volume 25, Number 2, Page 9, June 2017.  2. FREO2’s Webpage.  Site Visit on June 29, 2017.  3. Pneumonia (The Journal).  FREO2: An Electricity Free Oxygen Concentrator.  Bryn A. Sobott (, School of Physics, The University of Melbourne, Parkville, Victoria, Australia.  Phone +61-3-83445075) David J. Peake, James F.P. Black and Roger P. Rassool.  Volume 6, Page 115, November 2015.  4. Email to Shrimp News International from Kevin Rassool.  Subject: For Kevin Rassool.  August 3, 2017.

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