Achieving water reuse: It’s takes a certain chemistry
At the heart of any water treatment is balanced water chemistry. The pH value must be just right for whatever the application: whether drinking or industrial processes. Too alkaline and not only is it undrinkable but it will affect infrastructure through scaling and if the pH is too low then corrosion damage can occur. This is why Linde developed the SOLVOCARB® system – a reliable, eco-friendly way to accurately neutralise the alkaline pH value of water using carbon dioxide (CO2). Reliability and ecology are particularly important in the desalination process: where fresh water is obtained from seawater – one means of lessening the demand on groundwater.
“Everything is pointing towards desalination,” confirms Darren Gurney from the Linde Global Development Centre. Gurney is a water treatment expert who has seen countless desalination plants go on stream in the last few years – due in no small part to Linde’s SOLVOCARB® system.
After adding important substances such as calcium oxide (lime) to improve the hardness of the raw desalinated water (known as re-mineralisation), the pH is then corrected to place it in the range required by the regulations for drinking water or industrial process requirements. This is achieved by adding CO2.
“The costs per cubic metre of treating water have dropped significantly in the last 15 years,” reports Gurney, adding that this has less to do with energy prices and more to do with technology and continued innovation. Owing to the shortage of groundwater, the Middle East is now home to 70% of the world’s desalination plants. In Oman, for example, Linde’s SOLVOCARB® system will be used in Suez’s new desalination facility in Barka, which, with a capacity of 281,000 m3 per day is the country’s biggest reverse osmosis drinking water project. It will start supplying the Sultanate with drinking water by 1 April 2018.
Over time, SOLVOCARB® has become more and more efficient, opening up new opportunities and expanding the application spectrum. As a result, companies are increasingly turning to CO2 and SOLVOCARB® to treat water for industrial purposes.