Osmosis is the natural diffusion of water through a semi-permeable membrane from a solution containing a low concentration of dissolved solids to a solution having a higher concentration of dissolved solids. A sports drink syrup provides the osmotic pull to move the water through the membrane filter.

HTI filter systems deliver the highest purity possible. In independent laboratory tests, HTI filters meet or surpass reductions for bacteria, viruses, and cysts as specified by the EPA for water purifiers. The filters are extremely reliable; they simply don't clog. Unlike other water filters, no pressure is required for the filtration process which can cause the system to clog. HTI filters are hands free. HTI's tactical filters are fill-and-go systems. Spending less time at a water source lets our forces concentrate on more important tasks and allows for increased situational awareness.

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.

The Forward Osmosis Process

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 sports drink syrup “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 sports drink syrup “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 sports drink syrup 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.


Forward Osmosis Versus Reverse Osmosis

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.

Technology Background

HTI is the developer of the most advanced form of water filtration technology in the world.
HTI has more than twenty years experience in research and development of advanced membrane technology, and has developed the world’s first commercially viable line of forward osmosis membrane products.

This technology has been used by NASA, the US Department of Defense, branches of the US military and in aid of relief organizations around the world.

HTI originally developed FO for “cold” concentration of food and beverage products. Pilots were carried out at OSU Food Science, UC Davis and a California tomato plant demonstrating quality benefits and energy savings.

HTI used the same membrane innovation for waste reduction /water recovery for NASA and landfill leachate.