Why we need a smarter desalination, not just a bigger one
By Professor Dato Dr Ahmad Ibrahim
For decades, the solution to global water scarcity has felt deceptively simple: if we run out of fresh water, we’ll just make our own. And we have. The Gulf states now embroiled in the US-Iran conflict depend entirely on desalination for water. Desalination has transformed from a futuristic fantasy into a daily reality for millions, a testament to human engineering prowess. But a new review by researchers Anwur Alenezi and Yousef Alabaiadly, published in Energy Nexus, throws cold water on the notion that we’ve got this all figured out. Their analysis of emerging technologies isn’t just a catalog of cool science; it’s a reality check. It tells us that the future of our water supply depends less on building bigger plants and more on building smarter systems.
The review arrives at a critical juncture. We’ve spent the last half-century perfecting the heavyweights of the desalination world: thermal behemoths like Multi-Stage Flash (MSF) and membrane marvels like Reverse Osmosis (RO). These are the workhorses that keep arid cities from turning to dust. But as Alenezi and Alabaiadly’s work implicitly argues, relying solely on these established players is like fighting a 21st-century war with 20th-century tactics. The challenges are evolving—high energy consumption, environmental damage from brine disposal, and the relentless battle against membrane fouling—and our tools must evolve with them.
The true value of their review lies in the “future outlook”—a survey of the emerging technologies that promise to rewrite the rulebook. This isn’t about one magic bullet, but a diverse arsenal of approaches, each targeting a specific weakness of the old guard.Take, for instance, the focus on solar-powered passive desalination (SPPD) and solar electrochemical distillation (SED). For too long, the desalination industry has been an energy glutton, often powered by the very fossil fuels that exacerbate the climate crisis driving water scarcity. These solar-driven methods aren’t just “green” add-ons; they represent a fundamental rethinking of the energy-water nexus. They offer a tantalizing vision of decentralized, off-grid units providing fresh water to remote communities without plugging into a carbon-intensive grid. It’s about democratizing water production.
Then there’s the nuanced promise of Capacitive Deionization (CDI). Instead of brute-forcing water through a membrane, CDI uses an electrical field to gently pull charged ions (salt) out of the water. It’s a lower-pressure, potentially lower-energy alternative, particularly for the brackish water that plagues inland communities. This isn’t a replacement for massive seawater RO plants, but a perfect example of “horses for courses”—using the right tool for the specific job.
Perhaps the most intellectually exciting frontier highlighted is the integration of Machine Learning (ML). We are generating immense amounts of data from desalination plants, but we’ve been poor at listening to it. ML offers the ability to move from reactive maintenance to predictive optimization. Imagine a plant that can forecast a fouling event before it happens, adjust its chemical dosing in real-time, or dynamically balance its energy use with the fluctuating supply of solar power. This isn’t just an incremental improvement; it’s giving the entire process a brain.
However, the review, whether explicitly or by implication, delivers a sobering message alongside the optimism. Many of these technologies—Forward Osmosis (FO), Membrane Distillation (MD), microbial desalination—are still lab-bound or operating at pilot scale. They face the dreaded “valley of death” between a promising academic paper and a commercially viable product. They wrestle with their own demons: finding the right draw solution for FO, managing membrane wetting in MD, or simply proving they can operate cost-effectively 24/7 for decades. At least they hold promises.
This leads to the core takeaway: the future isn’t about choosing between RO and these new kids on the block. It’s about hybridization. The most profound innovations won’t be single technologies, but the intelligent combination of them. Imagine a system where FO pre-treats difficult water, reducing the load on a downstream RO system, which is then optimized by an AI, with its brine waste sent to an MD unit to extract more water and valuable minerals. This circular, integrated approach, where the waste of one process becomes the feed for another, is where the real revolution lies.
Alenezi and Alabaiadly’s review serves as a vital piece for this complex territory. It shows us that the path forward requires a shift in mindset. We must stop thinking like engineers building a single, monolithic machine and start thinking like ecosystem managers, designing a diverse and interconnected network of solutions. The goal is not just to produce more water, but to do so intelligently, sustainably, and equitably. The technology is emerging; now we need the wisdom to deploy it.
The author is affiliated with the Tan Sri Omar Centre for STI Policy Studies at UCSI University and is an Adjunct Professor at the Ungku Aziz Centre for Development Studies, Universiti Malaya. He can be reached at ahmadibrahim@ucsiuniversity.edu.my.