Forward Osmosis Breakthrough

A newer device created and patented by an NMT mechanical engineering professor has shown major promise in cheaply and efficiently producing clean, usable water from brackish water, seawater and other untreated water. The university is now hoping to partner with private funding to advanced the technology further.

New Mexico’s water sources
“We take it for granted that water will be there forever, which is not true,” said Dr. Ashok Ghosh, an associate professor of mechanical engineering at New Mexico Tech. “Everywhere now, we are seeing the scarcity of water, not just in this state of New Mexico, or the U.S., it’s the whole world.”

Over the last several years, Ghosh has been working on a “green” desalination project at NMT, aimed at removing dissolved salts and other particulates from natural brackish water and so-called “produced water,” a byproduct of oil drilling. Brackish water most lies underneath the surface, too salty to use for drinking water or irrigation purposes, according to NMT research.

“We have plenty of sources of this, but then this water has got such a high salt content that you have to clean it,” said Dr. Ghosh, speaking of brackish water. “You have to remove that salt, and some of those other contaminants before you can use it.”

Meanwhile, there’s also a significant amount of produced water, generated in the oil-rich Permian Basin, one of the world’s most prolific oil fields. In the process of drilling for oil, crews generate billions of barrels of water contaminated with oil, grease, suspended solids and dissolved solids. According to the New Mexico Environment Department, much of that produced water isn’t recycled in part due to the high costs of treating it.

“These trucks will go to all of these different sites, they’ll collect this produced water, and there is this disposal pond,” Dr. Ghosh said of produced water. “They’ll bring it to disposal pond, then they will dump it there. Some of the oil, which is floating on the top, they’ll skim it out and then the rest will be evaporated, and that’s how they were disposing this produced water.”

The machine
With a $2-million federal grant, Dr. Ghosh created a forward osmosis water filtering machine. While the process of forward osmosis isn’t new, Ghosh’s machine represents a unique breakthrough.

First, the forward osmosis machine uses less energy than a reverse osmosis machine (which requires excessive, energy consuming pressure.) Second, the device uses a special sweeping system, which keeps the water filter (a semi-permeable, plant-based membrane) from getting clogged up.

“We kind of perfected that technology and then we put everything in a trailer,” said Dr. Ghosh, speaking of the device and a subsequent test near oil fields in Jal. “We compared the forward osmosis with the reserve osmosis and we saw very good results.”

Dr. Ghosh says the results showed as many as 65 times [more] throughput than a similar forward osmosis test conducted at from Yale University. The results have New Mexico Tech looking to take the device to market.

What’s next?
New Mexico Tech’s Office of Innovation and Commercialization is now looking for private funding for the next phase of Dr. Ghosh’s device. Executive Director of the office, Myrriah Tomar says the device is at a Technology Readiness Level (TRL) of 6 out of 9, meaning it has a stronger chance of breaking through on the commercial market.

“[Ghosh] has a prototype, he’s demonstrated it and I think now we’re looking for someone to partner with and any funding to take this to the next level,” Tomar said. “Green desalination is important because its addressing clean water, and, as you know, with climate change, the scarcity of water is [increasing], so having technology like this is becoming very important.”

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Taxonomy

• Brackish Water
• Desalination
• Forward Osmosis