Oneka Technologies, a Canada-based startup, has unveiled its environment-friendly desalination technology that works by using power from the waves at sea. This environmentally friendly approach could help countries tend to the water needs of their population without worrying about its climate impact.

Out of the total water available on the planet, a mere 3% is fresh water that can be used. The rest is salty sea water unsuitable for drinking or industrial usage, and desalination plants have helped put this water to some use.

Nevertheless, desalination is an energy-intensive process, and none of it comes from renewable sources. According to the International Desalination Association, desalination plants have doubled in the past decade, and the sector is expected to grow at 9%. In such a scenario, an environment-friendly solution would be helpful in a world looking to move away from fossil fuels. 

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Conventional desalination plants work in either of these approaches – thermal or membrane. In the thermal process, seawater is heated till the water evaporates, leaving the salt behind. The evaporated water is cooled, collected, and made available for use.

In the membrane approach, seawater is passed through a semi-permeable membrane that takes in the salt. This approach is also energy-intensive but comparatively better than the thermal treatment.

Oneka's approach to desalination is an improvement over the membrane approach. This is achieved by using buoyant machines that are anchored to the seabed and using a membrane system that is powered by the waves. 

The machines absorb energy from the waves and convert it into mechanical force, which is used to draw in the seawater. A quarter of the water is circulated inside the desalination system, and purified water is pumped using mechanical power to the shore. 

 

Advantages of the system

The entire system is mechanically driven and works without electricity. The desalination machines are being built in three sizes, with the most enormous measuring 8m x 5m. The devices need 1m-high waves to work, and the largest can produce 49,000 litres of water daily. The modular machines can be connected to generate more significant amounts of water.

Besides not emitting carbon during the process, the system is marine life-friendly. The waste from conventional desalination plants contains concentrated levels of salt or brine that need to be processed further before being discharged into the sea. If salt levels are too high, they kill marine life in the area, creating a dead zone.

Oneka's machines use three-quarters of seawater pulled in mechanically to mix the concentrated salt from the membranes and release it back into the sea without raising sea levels by a high degree.

Seawater intake happens through 60-micron inlet holes, too small to take in any marine life. According to its website, the anchors of the system are also converted into artificial reefs a few months after their installation. 

Oneka expects its desalination machines to be commercially available next year.