As we stand at the precipice of a rapidly evolving global landscape, one thing has become abundantly clear: our relationship with water is in desperate need of a radical transformation. The alarming projections are hard to ignore – in just two decades, three billion people will join the global consumer class, accelerating the degradation of our natural resources and escalating the competition for them. And nowhere is this growing imbalance playing out more acutely than in the water sector.
Already, scarcity is so pronounced that we can no longer reach many of our desired economic, social, and environmental goals. If we continue on our current trajectory, global demand for water will exceed viable resources by 40 percent by 2030. The crisis is real, and it’s staring us in the face – from rivers that no longer reach the sea, to exhausted aquifers in the Arabian Peninsula, to polluted water sources like Lake Tai in China.
But here’s the thing: the root of this challenge is not some complex political or economic system. It’s the violation of a fundamental principle – the zero-waste imperative that lies at the heart of any truly sustainable, circular economy. We’ve pushed water into a linear model, where it becomes successively more polluted as it travels through the system, rendering future use impossible. This practice transforms our most valuable and universal resource into a worthless trickle, creating high costs for subsequent users and society at large.
Redefining the Water Cycle: Embracing the Circular Economy
It’s time to stop viewing water as a linear commodity and start embracing it as part of a circular economy – one where it retains its full value after each use and eventually returns to the system. This shift will require a complete mindset change, but it’s a change that must happen immediately given the urgency of the situation.
Think about it this way: if we consider water to be a product, just like any other, then we must follow the same strict design rules applied to a circular economy. That means keeping it in a closed loop under zero-liquid-discharge conditions and reusing it as much as possible. The goal is not to keep water free of contaminants, but to manage the integrity of the closed-loop cycle.
On the other hand, if we treat water as a consumable, then it must be kept pure and only brought into solution or suspension with matter that is easy or profitable to extract. All water, including freshwater and greywater, should flow into subsequent cascades where it may be used for another purpose. Whenever possible, we should be extracting energy and nutrients from this consumable water, taking advantage of the revolutionary new techniques that are emerging.
Unlocking the Potential of the Circular Water Economy
So, what does this circular water economy look like in practice? Well, let me share a few examples that are already making waves in the industry.
Extracting Energy: It’s now commercially viable to generate heat and power from sludge and other organic wastes through a process called thermal hydrolysis. This involves boiling the materials at high pressure, followed by rapid decompression, which sterilizes the sludge and makes it more biodegradable. Facilities like the Billund BioRefinery in Denmark are leading the charge in this area.
Extracting Nutrients: We can now recover a wide variety of substances from water, reducing both waste and costs. For instance, the potassium hydroxide used to neutralize hydrofluoric acid in alkylation units can be extracted, decreasing costs by up to 75 percent. And substances like polyhydroxyalkanoates and other biodegradable polyesters can be removed from sludge, turning former “contaminants” into valuable resources.
Reusing Water: Innovative membrane-based treatments are allowing us to separate water from contaminants, enabling reuse and commercialization on a grand scale. From greywater to NEWater (Singapore’s high-grade reclaimed water), these technologies are making it possible to reuse water in ways we’ve never seen before. Not only that, but new source-separation systems are reducing the mixing of chemical-carrying industrial and household wastewater, making purification much easier.
Preventing Contamination: The Key to a Truly Circular Water Economy
But as impressive as these advancements are, the creation of a truly circular water economy will eventually require even more radical solutions. Because the real key to success lies in preventing impurity and contamination in the first place.
Take the case of the European Union, where 95 kilograms of nitrate per hectare are washed away from fields into rivers – an amount higher than the 80 kilograms allowed. Discontinuing this process would reduce both waste and contamination, truly closing the loop. Or consider the situation in Saudi Arabia, where water used for agriculture comes almost exclusively from fossil aquifers that will be depleted in a few decades. Here, the solution lies in embracing new irrigation sources, such as greywater, and following more stringent guidelines for reducing waste.
The good news is that most hydrological systems are flow systems – rivers or replenishable aquifers. This means that water can be withdrawn or consumed as long as the volume taken does not exceed the minimum environmental flow required to keep the ecosystem intact or the natural replenishment rates. In other words, you can’t be more circular than managing the water balance of a river basin in a rigorous and integrated fashion.
Leveraging Existing Assets for a Circular Water Future
But the transition to a circular water economy isn’t just about preventing contamination or managing water flows. It’s also about maximizing the benefits of the extensive water infrastructure we’ve already deployed around the world. Our global water networks and treatment plants, worth an estimated $140 billion, consume about 10 to 15 percent of national power production. By following the principles of a circular economy, we can find ways to optimize these assets and extract even more value from them.
For instance, utilities could allow telecommunication companies to install fiber cables through their trenches for a fee, and then charge for their maintenance. Or they could use their sewage systems and wastewater-treatment facilities to collect and treat preprocessed food waste with sewage sludge, generating heat for thousands of homes, as New York State has already begun doing.
But the real game-changer is the idea of selling performance, not water. Instead of charging by the cubic meter, utilities could pay consumers for curbing use and then sell the conserved volume – termed “nega water” – back to the system. This would require a major overhaul of rate-setting mechanisms, but it’s a shift that could have a profound impact on water conservation and the circular economy.
Embracing the Circular Water Future: Opportunities for Innovation and Collaboration
As I mentioned earlier, the transition to a circular water economy holds much promise. It would replace scarcity with abundance and greatly reduce the resources needed to run our global water infrastructure. And at some point, it might even eliminate rapidly growing cleanup costs because no harmful substances would ever be added to the water supply.
But to make this vision a reality, we need to embrace a new generation of designers, power engineers, yield managers, ecosystem-services marketers, and synthesis-gas tycoons. We need to foster product-design partnerships between wastewater operators and producers, create resource-positive utilities, and find ways to extract value from water as a major driver of yield in industrial processes.
We also need to tackle the challenge of basin management, which often fails due to the complexity of multiparty contracts and the need for a deep understanding of hydrology and engineering. And let’s not forget the opportunity to aggregate local organic waste flows and create vibrant markets for fertilizer components, helping communities deal with their sludge and organic waste problems while also supporting sustainable agriculture.
The truth is, the water sector is uniquely positioned to lead the charge in this circular revolution. With its advanced technologies and proven record of multistakeholder agreements, it’s the natural starting point for a transition that could have far-reaching implications for our entire global economy.
So, are you ready to dive in and reimagine the future of water resource management? Because the time to act is now, before localized droughts and shortages become a global crisis. By embracing the principles of the circular water economy, we can replace scarcity with abundance and build a more sustainable, resilient, and prosperous future for all.
And who knows, maybe along the way, we’ll even discover a few unexpected opportunities to transform the way we manage wastewater and unlock new sources of value for our communities. The possibilities are endless, my friends. Let’s get to work!