New Approach To Drinking Water Desalination Amounts To Significant Energy Savings

Many countries around the world rely on special processes to obtain fresh drinking water. One of the most common is desalination: the process of taking saltwater and turning it into fresh, drinkable water. This method is vital for those living in arid climates and it will likely be needed for more people in more places.

This is due in part to the effects of drought brought on by climate change, deforestation, and other issues. Although desalination has served as a reliable solution for drinking water supplies, it requires a great deal of energy, which poses its own supply problems for the present and future. Fortunately, a new approach to a process known as reverse osmosis may offer a solution.

Desalination Demands Major Energy

Ordinarily, desalination works by creating a high-pressure flow of seawater that then undergoes a special type of filtration. Using high-power pumps, the water is pushed through a unique, multi-layer membrane that removes suspended minerals, which turns it into drinkable water. This process is called reverse osmosis. The high-pressure flow is essential and requires many pumps and other equipment, which uses a lot of energy and contributes to the release of carbon.

Engineers from Perdue University have developed an alternative that would greatly cut the energy needed for desalination. “Batch reverse osmosis” works in a similar manner as reverse osmosis desalination. But instead of relying on a constant, high-pressure flow, the new system, uses an incremental or batched approach, which can process a comparable volume of water with less energy consumption.

The El Prat Desalination Plant, a seawater reverse osmosis facility near Barcelona, Catalonia. Credit: James Grellier

Although batch desalination is not a new concept, implementation has proven to be unfeasible in the past, mainly due to the downtime needed in between batches. This stifled input and fast nullified any gain from reduced use of pumps. The newly engineered approach has addressed this issue with a special piston tank.

Revitalizing An Old Concept With A New Process

The piston tank makes it possible to carry out a batch-based reverse osmosis process while simultaneously queuing more seawater for processing, which automatically eliminates the gap between batches. The simultaneous movement of batch water with queued seawater, which is filled into a designated section of the piston tank, makes the process incremental but also almost continuous. The ongoing processing and filling of the piston tank means that energy consumption is greatly reduced while a comparable output is maintained.

Little Powlett River and rig near Wonthaggi desalination plant. Credit: Peter Campbell

Batch reverse osmosis that uses this piston tank system can also be scaled based on need. It can be implemented on a scale that suits municipally-run desalination plants, as well as a household model that’s roughly the size of a kitchen appliance. This type of freshwater generating solution poses an important potential for a future where water security is predicted to be a critical issue.

Will batch reverse osmosis soon become a standard for desalination plants and water supply resources? Comment with your thoughts.

ABOUT Perdue University

Purdue University West Lafayette is the system’s flagship campus and, according to The Wall Street Journal and Times Higher Education, a top-five U.S. public university with the fourth-highest international student enrollment. Indiana’s land-grant university, Purdue offers more than 200 undergraduate programs, more than 80 graduate programs and professional degrees in pharmacy and veterinary medicine.

Indiana University-Purdue University Indianapolis (IUPUI), Indiana’s premier urban research and health sciences university, is a U.S. News & World Report top-200 national university. IUPUI offers more than 350 undergraduate, graduate and professional programs from Indiana University and Purdue University, including more than 95 Purdue programs that serve nearly 6,000 students.

Located at campuses in Hammond and Westville, near Chicago, Purdue University Northwest offers nearly 70 undergraduate and graduate programs. It features an honors college and faculty-led student research in a vibrant and diverse academic community.

Article Sources

https://techxplore.com/news/2021-05-breakthrough-reverse-osmosis-energy-eff…

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