Forward Osmosis: A Green Technology
Forward Osmosis (FO) is a remarkable new technology that turns muddy, contaminated water, into a clean and refreshing drink.
Forward Osmosis Technology is also a remarkable new technology that removes difficult toxic waste and pollutants from industrial waste streams.
- Osmosis is a natural equilibrium process
- Two liquids are separated by a special proprietary membrane that allows only water to pass
- Water passes from one chamber to the next by diffusion until the solids concentration on both sides of the membrane are equal
Forward Osmosis Membranes reject organics, minerals and other solids — similar to reverse osmosis (RO) — but resist typical fouling problems
It is the process of two liquids seeking equilibrium that creates the “power” in Forward Osmosis. In the example above, the permeate side of the membrane contains a salt “draw” solution which has a higher osmotic potential than the dirty feed water on the other side of HTI’s proprietary membrane. That higher osmotic potential in the salt “draw” solution is the power source nature provides to drive the filtration process. The water moves through the membrane, is filtered in the process and dilutes the higher concentration salt water on the permeate side.
Forward Osmosis Enjoys Several Unique Technological Advantages.
- FO overcomes fouling limitations inherent in pressure driven membrane separations allowing proper filtration and concentration of difficult products and waste streams.
- FO can process feed streams; a source of dirty or polluted water containing high levels of suspended solids.
- In separations driven by hydraulic pressure (such as RO) all components of a feed stream are unselectively forced against the membrane surface.
- In FO, osmotic pressure, which is hydraulic pressure created by Osmosis as water passes through a semi-permeable membrane into a more concentrated stream, selectively draws molecules through the membrane avoiding membrane fouling and compaction.
- FO is a process normally occurring in nature that, when harnessed for water filtration and liquid transfer, requires little or no electricity or external power source.
In this example, the process of Reverse Osmosis (RO) is compared with Forward Osmosis (FO). RO typically requires high pumping pressures, which require high energy usage to force the feed solution against a very tight membrane material and force the filtered water through the membrane to the clean water side. During that process all solutes and pollutants on the dirty water side are forced against the membrane material, under high pressure, which compounds RO’s sensitivity to fouling and need for relatively clean feed streams. Conversely, FO operates at very low pressure, simply adequate to circulate the fluids, and the natural osmotic pressure in the draw solution pulls water through the membrane, leaving solids and foulants behind in the concentrated feed solution.
HTI originally developed Forward Osmosis for “cold” concentration of food and beverage products. Projects were carried out at Oregon State University Food Science, UC Davis and a California tomato plant, demonstrating quality benefits and energy savings.
HTI uses the same membrane innovation for waste reduction (water recovery) for NASA and many private commercial enterprises.
HTI is the exclusive manufacturer of commercial forward osmosis membrane material.
In summary, HTI has, through its exclusive manufacture of unique proprietary membrane materials, made possible the capture and duplication of a natural occurring process in nature turning it into a “Green” technology; a Green technology that is capable of solving many of the world’s most difficult water filtration and recycling problems.
Forward Osmosis technology can be applied to various industries including: