Novel Method for the Production of Upgraded and Fresh Water from Saline, Brackish and Polluted Waters

Web Published:

Princeton Invention # 06-2206


The availability of fresh water for drinking, domestic and industrial uses is a growing problem in many parts of the world. Reverse osmosis and evaporation methods are currently in wide use for water remediation, notably in Saudi Arabia where potable water is produced on a large scale from sea water. Electrodialysis and freezing methods have been less applied. The economics of all these processes depend on the water source and on the facilities and environmental problems at the intended site.


Researchers in the Engineering Department at Princeton University have developed a novel method for the production of fresh water using alkane hydrates (clathrates).The Princeton method outlines a process which overcomes the high cost associated with using alkane hydrates. This novel method uses a separation method in which the hydrate is formed at the temperature of the source water and at a pressure between one atmosphere and (preferably) less than 10 atmospheres, with a method for performing nuclei to minimize pressure and accelerate growth of the solid phase. The source water (e.g., the sea) acts as the heat sink for forming hydrate and as the heat source for melting separated hydrate in a process in which the pressure is cycled between one and 10 atmospheres or less


The hydrate formers meeting the required pressure-temperature properties may be simple one-component hydrates or complex hydrates or combinations of simple and complex hydrates. With complex hydrates the primary clathrate former gives a structure in which the small secondary cavities can be filled with one or more second guest species, thereby raising the melting temperature at a given pressure. The hydrate formers can be gaseous or liquid over all or part of the pressure cycle, offering a range of design options. If the hydrate formers are liquids, clathrate formation can be accelerated by the addition of dilute safe oil-soluble surfactants to increase the interfacial area. The clathrate formers can be biologically safe and readily removed from the fresh product for recycling at the decompression stage. The heat-sink water from the high pressure clathrate formation stage may be recycled to improve the heat source in the decompression stage, or vice-versa for partial pre-cooling. Advantage may also be taken of the difference of water temperatures at different depths at the plant site. The hydrate is formed as a pump- able slurry separable by coarse filtration, gravity or mild centrifugation prior to decompression to recover the fresh water and recycle the clathrate formers.


Several hydrocarbons which show clathrate formation at temperatures and pressures appropriate for the proposed process have been identified as candidates for a design study on a range of source water chemistries and temperatures. Research for other multi-component hydrates will expand the temperature and pressure choices for plant designs relevant to particular locations



Princeton is currently seeking industrial collaborators to further develop and commercialize this technology. Patent protection is pending.


For more information on Princeton University Invention # 06-2206, please contact:



                                Laurie Tzodikov

                                Office of Technology Licensing and Intellectual Property

                                Princeton University

                                4 New South Building

                                Princeton, NJ 08544-0036

                                (609) 258-7256

                                (609) 258-1159 fax



Patent Information:
For Information, Contact:
Laurie Tzodikov
Licensing Associates
Princeton University
Brian Pethica