Forward Osmosis – Solving Tomorrow’s Water Challenges Using Nature’s Remedy

Nature has an ingenious way of extracting water, but does it have the potential to solve many of today’s global water challenges? Before going into more details on how nature’s way of extracting water can help cut energy usage in water treatment processes, an appreciation is needed of why energy reduction in water treatment is an essential prerequisite for continued global development.

Since water is used in all energy production processes and energy is used to generate fresh, potable water from impaired sources, water and energy are two sides of the same coin. Factor in that global fresh water resources are rapidly declining and energy prices are one the rise due to over-utilization of fossil fuels, you quickly realize that energy reduction in water treatment processes will make a tremendous positive impact on the challenges faced in this water-energy nexus.

Moving back to nature’s way of extracting water, you may have wondered how trees are able to extract water from the soil in which they grow to the leaves in the treetops? Or how mangroves are able to extract fresh water from the seawater surrounding their roots? Given the obvious lack of electrically powered high pressure pumps, nature has come up with it’s own way of generating the pressure needed to transport water in trees and to extract fresh water from seawater in mangroves. It turns out that nature extracts water by utilizing the principle of forward osmosis in which water diffuses spontaneously (and without the input of energy) across a semi-permeable membrane from a low concentration solution on one side of the membrane to a high concentration solution on the other side of the membrane. The driving force for forward osmosis processes being the difference in osmotic pressure between the aqueous streams on either side of the forward osmosis membrane.

Coming back to the trees and mangroves mentioned earlier, the intracellular solution of root cells contains high concentrations of sugars and other dissolved molecules, which in turn generate a large enough osmotic pressure to extract water from soil and seawater respectively and transport this water throughout the stems and leaves of these amazing biological systems.

Now, how can water transport in trees help solve the looming water challenges facing our world today? Well, fortunately scientists have been able to develop artificial forward osmosis membranes and systems for industrial water treatment applications. And since forward osmosis systems do not require electrical energy inputs other than the energy needed to pump solutions across its membranes, it is potentially possible to reduce the overall energy consumption of water extraction by 90% compared to traditional pressure driven technologies such as reverse osmosis and nano-filtration.

Wide-spread adoption of forward osmosis systems in industry is still limited due to lack of high-performing, large-scale system capacity as well as industry preference towards proven technologies with long-term operational track records.

A number of startups and tech companies are working in the area.


Oasys Water 


HTI Water

As well as ongoing research projects at a number of universities and labs around the world are working hard to commercialize forward osmosis technologies, so don’t be surprised if you – in the near future – start running into examples of forward osmosis being used to treat water in industries or even households.

A Perfect Storm for Water

‘Growing world population will cause a “perfect storm” of food, energy and water shortages by 2030′. That is what a UK Government chief scientist told attendees at the Sustainable Development conference in London yesterday. Prof. Beddington told the group that demand for food and energy will jump 50% by 2030 and for fresh water by 30%, as the population tops 8.3 billion.

Despite this, investment in water deals represented just 1.8% of the total investment in the Clean Technology area in 2008. There are number of reasons for this and also signs that this is changing.

The Venture Capital Community has been slow to invest in the water sector. Last year out of a total investment of $8.4 billion into clean technology ventures, just $148million (1.8%) is reported by the Cleantech Group by having been made into water. Why?

Some companies are not convinced that there is enough activity in the sector. Others feel it is a conservative market. However DFJ just made their first investment in water by investing $10M into Oasys Water, a US company with a forward osmosis technology.

The Artemis Project is running a ‘Water Top 50’ to identify companies with game changing strategies in the water sector and to demonstrate to the VC community that there are quality opportunities in this space. Global Water Intelligence has number of potentially disruptive technologies as entrants in their ‘Water Idol’ competition and overall several Water Indices, while showing losses, are still outperforming major stock indices.

One of the problems with water is that we only use it once. Of the wastewater which is collected globally, 38% is actually treated and only 5% of that is actually re-used. Michael Braungart, the author of ‘Cradle to Cradle – remaking the way we make things’, is addressing this issue at the Water Meets Money Conference in Zurich with a talk entitled ‘The End of Wastewater’.

So yes, it may be a perfect storm in terms of water shortages, but it may also be a perfect storm which will see innovation, the end of wastewater and new ways of using and managing this resource.

This post is submitted by Paul O’Callaghan founding CEO of O2 Environmental .