Water. It is the essence of life. Our bodies need it, plants need it, animals need it, and it is an integral part of every ecosystem. Such an important resource, but it can be almost impossible to obtain in certain regions of the world, especially during longstanding droughts. The topic today for environmental technology and innovation is important because as climate change continues to ravage the planet, we are seeing increased droughts both in duration and frequency in much of the world. This is especially troubling in poorer countries with minimal resources. To ensure the survival of the cultures in those regions, we need to come up with a viable and cost-effective solution to the water demand. The solution? Desalination.
Desalination technology has been around for some time now in various forms, but it has always been too expensive to be sustainable economically for most of the population. However, research and development at Purdue University have been revitalizing the technology for reverse-osmosis desalination. Reverse-osmosis refers to “flowing seawater over a membrane at high pressure to remove the minerals” as described in the news release. The process itself is mostly limited in economic feasibility due to the high energy requirement. Normally, the technology has worked best by running the system continuously at full capacity without stopping. But this means the energy input needs to be maximized the entire time as well. The new technology developed by Purdue University aims to change this by using a process called batch reverse-osmosis.
The batch strategy is more energy efficient because you only need to run at full capacity for a fraction of the time. Basically, for each batch, the process takes about one to two minutes where the energy is ramped up over that time and therefore is not at 100% power the entire time. This saves significant energy costs. However, in the past, the batch strategy was avoided due to the maintenance and downtime of refilling the piston tanks for each new batch. Whereas the improvement of Purdue’s new design allows the next tank to fill while the other side is being desalinated. Then the process repeats so no time is wasted between batches. The technology also has the capabilities of being small enough to fit in a person’s hands, which means it could be distributed to individual households as well as in large scale municipal plants.
As the climate crisis continues, it’s clear that water will become more and more scarce, so being able to capture potable water from the vast oceanic resource is one of the most important technologies of the future.