Switchable water: a wastewater solution

Forward Water Technology has developed a proprietary desalination process
Forward Water Technology has developed a a new “switchable salt” additive for desalination

Globally, 884 million people lack access to clean water. This is one of the greatest challenges facing humanity today. Indeed, many of our most significant societal challenges, such as famine, disease proliferation and political unrest, can be linked to this issue.

Furthermore, the recovery and re-use of industrial wastewater, which is a significant consumer of our fresh water reserves, must be enhanced. Yet we do have access to an abundant source of water—saltwater as found in our oceans.

While most of us in Canada are unaware that water is becoming an increasingly scarce commodity, desalination of sea water has already become a large industrial sector representing over US$20 billion in turnover per year and growing at a rate (CAGR) of 9.4 per cent per annum. This market is mainly comprised of operations where no other alternatives are available.

Currently, processes such as thermal distillation (boiling water with intense energy input then condensing the resulting vapours) and reverse osmosis (using high pressure to squeeze salt water through a selective membrane which allows water to pass through but not the dissolved salts) are being used to convert seawater into drinking water. Approximately 78 billion litres of salt water are purified by these methods every day. However, these processes are costly and energy intensive. Purifying that much salt water uses over 28 million kWh of electricity a day, which is enough energy to power over 1.4 million Canadian homes.

Clearly, a more sustainable solution is needed. Furthermore, these incumbent technologies are limited in their ability to economically remediate industrial wastewater streams. Consequently, we need an environmentally and economically sustainable process to convert our abundant supplies of seawater into potable water that can also address the recovery of industrial wastewater.

Enter Forward Water Technology’s proprietary desalination process.

Forward Water has developed a new “switchable salt” additive that can be used to generate concentrated salt solutions by effectively “sponging” water from an area of low salt concentration (e.g. seawater, three per cent salt or process waste water, typically seven per cent salt) through a forward osmosis process. Unlike reverse osmosis, forward osmosis is a natural phenomenon that requires very little energy input. In fact, it’s the same process that regulates proper turgor pressure in the cells of all living things!

Through this process, water wants to naturally flow from the low concentration area to the high concentration area. When a selective membrane is used to separate the low and high concentration areas, only the fresh water moves from the input stream (either seawater or waste or produced water) into the “sponge,” i.e. the highly concentrated salt solution based on Forward Water’s proprietary switchable salt.

At this point, we have effectively “sponged” fresh water from the input stream into our “switchable salt” solution. However, the problem is not quite addressed. Indeed, the most innovative facet of Forward Water’s technology is the ability to switch this salt into gaseous byproducts. Once we have extracted (sponged) all of the fresh water from the input stream, we are able to “switch” the salt that comprises the draw solution.

Once switched, it transforms into gaseous byproducts, which simply effervesce out of the solution resulting in clean water.

Furthermore, the salt, which has been switched and bubbled out of the draw solution, can be collected and reused to regenerate a fresh batch of draw solution, i.e. the “sponge.” The whole process is effective, energy efficient, recyclable and cost effective.

Forward Water’s technology is an environmentally and economically viable method to generate potable water from seawater and significantly reduce the total volume of industrial wastewater that needs to be remediated.

Forward Water is currently working with its strategic partners to continue to develop this platform. The company is also seeking private investors to support the company’s growth and platform development. Once financed, the company will work with its strategic partners to design and commission a demonstration unit followed by a pilot unit with a desired throughput of 100 – 250 m³ per day.

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