Desalination without the impact: how smarter solutions can help

Smarter desalination starts here—Omyaqua helps reduce carbon footprint and improve water quality.

Omyaqua range solutions with a glass of water

There are over 20,000 desalination plants worldwide, providing water for more than 300 million people. As water scarcity spreads, this proven technology is becoming increasingly important. But the high energy demand and large installation costs make desalination environmentally and economically challenging. Nicholas Nelson, Director Innovation and Technical Marketing Water & Air Treatment at Omya, believes the industry must adopt smarter solutions to reduce its footprint.

The energy challenge behind every drop

“We are all under pressure to decarbonize manufacturing processes, and desalination is no exception,” Nelson explains. The two main methods—thermal distillation and reverse osmosis—are both energy intensive. While reverse osmosis has become more efficient in recent years and is now the dominant technology, it still requires between 2.5 and 3.5 kWh1 to produce just one cubic meter of water. And that’s before additional treatments make the water safe to drink.

One of those treatments is remineralization. Desalinated water cannot be used -directly because of its lack of buffer capacity and inherent chemical instability, which must be corrected before distribution. Adding calcium and magnesium improves stability and ensures that the resulting water is non-corrosive. There are a number of different ways to increase water hardness, alkalinity and pH but as Nelson explains, they have very different carbon footprints. “One of the most common methods of remineralizing soft water is lime dosing, used by the majority of desalination plants. There are a number of issues with lime but one of the key drawbacks is its high carbon footprint, which is ten times greater than, for example, calcium carbonate, a cost-effective alternative.”

Omya produces a range of high-quality calcium carbonates for remineralization and stabilization of soft water through calcite contactors. As one of the most abundant materials on earth, requiring little processing, calcium carbonate has a very low carbon footprint. Nelson says it offers operational benefits as well as environmental ones. “Our Omyaqua range is compliant with all drinking and process water standards. Omya has developed this product line specifically for drinking water treatment, including post-treatment of desalinated water. 

Omyaqua is available globally and represents products that meet the highest standards in purity and compliance, providing customers with peace of mind. Plant operators can choose the physical characteristics, for example particle size, porosity and purity, to give the best dissolution performance, whilst protecting their plant from the harmful effects of scale from lime. Operationally, calcium carbonate requires less carbon dioxide and produces less waste.”

Managing salty waste and building a circular future

Another major environmental concern is the waste produced by desalination plants. For every 100 cubic meters of freshwater produced by desalination, almost 150 cubic meters of brine are produced2, most of which is returned to the ocean. Nelson says that better brine management can reduce the environmental damage caused by these waste products. “Omya is a partner in the EU-funded Salteau project3 which is looking at mineral extraction from brine to recover essential resources such as calcium carbonate and magnesium hydroxide. This type of circularity will be crucial as desalination becomes more prevalent across the world.”

Omya is a global leader in mineral processing technology and is using its expertise to support the water treatment industry at a time when decarbonization, operational efficiency and human health are high on the agenda. As Nelson concludes, “Global water security will increasingly rely on desalination so it is incumbent on us to develop smarter solutions that will reduce its environmental footprint.”