Water scarcity has been referred to as the silent existential crisis of our time. Our planet has very little fresh water — and is running out of it quickly. Yet no one seems to be talking about it.
However, we do have significantly more saline water. With that, there’s good news, bad news, and more good news: The good news is that there’s a technology — desalination — to put that brackish water to good use. The bad news is that modern desalination is limited in its adoption due to cost, footprint, and sustainability concerns. The other good news is that a new technology developed by California-based company Active Membranes could ameliorate the desalination process and greatly enhance the world’s supply of freshwater.
“Our goal is to make desalination cost-effective, less complex, and easier to adopt so that every community, big or small, can afford and sustainably benefit from it,” said Arian Edalat, Co-Founder and CEO, Active Membranes.
A widely used method to remove dissolved salts and other contaminants from water is reverse osmosis (RO), which uses ultra-thin membranes that enable water under pressure to pass through the membrane while blocking salt and other contaminants.
Scaling and fouling — the buildup of salts and organic matter, respectively, on the membrane — are two common problems with such purification, though. To avoid scaling, RO membranes must be frequently backwashed and cleaned, which is neither time- nor cost-efficient.
So, Active Membranes has developed a novel approach to keep membranes clean. By applying an ultra-thin, electrically conductive coating on top of the membrane and then charging the surface with low voltage, the salt ions and other charged species in the water are pushed away from the membrane surface, reducing scaling and fouling. Edalat noted that the trick is, much like painting a car, the coating must be highly uniform and free from holes and defects.
“The active membrane is coated with a conductive material,” said Peter Fiske, Executive Director, National Alliance for Water Innovation. “Once the membrane is rolled into a spiral-wound module, the membrane itself is electrically activated. Not only does the electric charge on the membrane surface improve the flow characteristics of water through the membrane, but it also helps reduce the accumulation of materials that can block the surface. And the electrical signal itself gives information about the health of the membrane. Conventional RO membranes are completely passive; this one is active and informative.”
Indeed. In a recent field pilot in Ventura County, which tested the electrically active membranes against conventional membranes, the former demonstrated a 20- to 30-percent improvement in water production.
This is an important advancement: According to U.S. Geological Survey estimates, the amount of brackish groundwater in the U.S. is more than 800 times the amount of fresh groundwater pumped from all other sources every year. This new membrane technology could be quite the boon for access to clean agricultural and industrial water.
The original work was Federally funded and performed at UCLA to demonstrate the potential for coating RO membranes and electrically charging them. But the key breakthrough, Fiske said, came when the Active Membranes team realized some of the key benefits of this process and adapted the technology to a commercial system.
Furthermore, Active Membranes is not finished just yet. Edalat noted that there’s “a lot of interest in demonstrating this technology elsewhere in California. We hope to see Active Membranes improve the performance, and lower the cost of, desalination and water treatment in California and across the United States as well as the rest of the world. The demand we’re seeing has prompted us to start yet another round of investment to scale up our production capacity and overall bandwidth to expand our initial commercial install-base.”
This article was written by Andrew Corselli, Digital Content Editor, SAE Media Group. For more information, visit here .
Transcript
00:00:00 [Music] what we experience with these membranes is that we can maintain um at least the 15% higher recovery without the use of any [Music] pre-treatment our na'vi project is testing a novel membran material that we've developed electrically conducting reverse osmosis membranes which had the
00:00:30 potential of reducing the footprint and cost of desalination um significantly will be running our membranes against conventional currently available commercial membranes on a head-to-head basis typically membrane separation is a passive phenomena you pass the water through the membrane you change that phenomena into an active Separation
00:00:54 whereby by applying a low potential electricity on the surface of the the nbran module we enable membrane itself to inhibit a scanning of falling and by doing so um we'll give the membrane the power to um sort of mitigate its own operation without having to rely on too many extensive pre-treatment and other processes if we're ever going to do true innovation in terms of uh membrane
00:01:20 separation in general and water desalination we have to look at the Paradigm of Separation at the membrane level and I think that's going to have to be the next uh big step step to take this industry as a whole um into where it needs to be in terms of sustainability and costs and footprint and all of that [Music]
