Desalination Is Booming, But Faces a Saltwater Reality Check

by:Pragati Verma

This is the first article in a series on Saltwater for Pumps. Read Part 2

As population grows and economies expand, they are putting an immense strain on the world’s water supplies. According to the UN World Water Development Report 2024, 2.2 billion people worldwide have no access to clean drinking water. Climate change is threatening to exacerbate the challenge with prolonged droughts parching the land in some regions and unpredictable rainfall overwhelming infrastructure and contaminating freshwater resources in other areas.

In short, water resources are no longer reliable, making global water security a significant and pressing issue. The impact of water shortages extends beyond lack of access to safe and reliable drinking water. The economic activity dependent on water is an estimated $86 trillion, according to water market information platform Global Water Intelligence. Several industries, such as electric power plants, need lots of water for cooling and scarcity can disrupt their operations.

Combat Water Scarcity

As global freshwater sources become scarcer, desalination of saltwater into drinking water is emerging as a possible answer. Countries around the world are increasingly turning to saltwater desalination to combat water scarcity and ensure a sustainable supply of freshwater for drinking and irrigation purposes. Due to their arid climate and limited freshwater resources, middle eastern countries such as Saudi Arabia, United Arab Emirates, Kuwait and Qatar rely heavily on desalination to meet their water needs. Several other countries, including Spain and the US, are investing in desalination plants for seawater as well as brackish and wastewater. The most common form of desalination is reverse osmosis. This water purification process uses a semi-permeable membrane to separate water molecules from dissolved or suspended substances, which is an immensely energy-intense process, with pumps contributing a significant proportion. As a result, the pump equipment involved in the process of desalination needs to be as efficient as possible to reduce energy waste and improve sustainability.

The water industry is not alone. Power generation, chemical and industrial plants, which require vast amounts of water for cooling purposes, are increasingly exploring the use of saltwater for cooling systems through desalination processes. Desalinated seawater or brackish water can serve as a reliable alternative to freshwater, ensuing the continuous operation of a power plant even in freshwater stressed regions.

Prepare Pumps for Saltwater

Saltwater, however, is highly corrosive and abrasive. Traditionally, materials such as bronze, brass and/or rubber are used for pump bearings, which don’t hold up well in this type of operating environment.

It can damage equipment such as pumps in constant touch with seawater, brackish water, concentrated brine, and treatment chemicals. “Traditional, lower-grade, non-metallic or rubber wear parts in pumps require frequent replacement due to the abrasive environments in which they operate. Moreover, salinity in the coastal areas makes the surrounding air very humid and corrosive and wreaks havoc on pump efficiency and can cause damage, downtime, or failure,” says Greg Gedney, Industry Expansion Manager at Greene Tweed. Backed by his two-decades long experience in pumping technologies, he adds, “The abrasive and corrosive nature of seawater, brackish water, concentrated brine, and treatment chemicals can damage pump components made of traditional material, requiring more frequent replacement.

According to Dave Noblin, Product Manager of SEC Platform at Greene Tweed says, “By upgrading to components made of corrosion and abrasion-resistant composite materials, such as WR® and AR®, pump engineers can significantly lower the life cycle cost of pump operations by extending service life, reducing pump overhaul costs, and maintenance expenses.” This strategic selection of pump components, he explains, “will not just extend the lifespan of pump systems, but also pave the way for a more sustainable future.”

(A version of this article was earlier published in Hydrocarbon Engineering Magazine)

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