Powering desalination with the sun

Natasha Wright

PhD student Natasha Wright makes water safe to drink for rural, off-grid Indian villages.

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When graduate student Natasha Wright began her PhD program in mechanical engineering, she had no idea how to remove salt from groundwater to make it more palatable, nor had she ever been to India, where this is an ongoing need.

Now, three years and six trips to India later, this is the sole focus of her work.

Wright joined the lab of Amos Winter, an assistant professor of mechanical engineering, in 2012. The lab was just getting established, and the aim of Wright’s project was vague at first: Work on water treatment in India, with a possible focus on filtering biological contaminants from groundwater to make it safe to drink.

There are already a number of filters on the market that can do this, and during her second trip to India, Wright interviewed a number of villagers, finding that many of them weren’t using these filters. She became skeptical of how useful it would be to develop yet another device like this.

Although the available filters made water safe to drink, they did nothing to mitigate its saltiness — so the villagers’ drinking water tasted bad and eroded pots and pans, providing little motivation to use these filters. In reviewing the list of questions she had prepared for her interviews with locals, Wright noticed that there were no questions about the water’s salty taste.

“No one had ever asked them about that. And although this might sound obvious, people really don’t like the taste of salt,” Wright says. “So once I started asking, it’s all anyone would talk about.’”

“The biggest surprise of the project so far has been this salt issue, which was the thing that changed the entire purpose of the research,” she adds.

Almost 60 percent of India has groundwater that’s noticeably salty, so later, after returning to MIT, Wright  began designing an electrodialysis desalination system, which uses a difference in electric potential to pull salt out of water.

This type of desalination system has been around since the 1950s, but is typically only used municipally, to justify its costs. Wright’s project aims to build a system that’s scaled for a village of 5,000 people and still cost-effective.

While other companies are already installing desalination systems across India, their designs are intended to be grid-powered. When operating off the grid, these systems are not cost-effective, essentially blocking disconnected, rural villages from using them.

Wright’s solution offers an alternative to grid power: She’s designed a village-scale desalination system that runs on solar power. Since her system is powered by the sun, operational and maintenance costs are fairly minimal: The system requires an occasional cartridge filter change, and that’s it.

The system is also equipped to treat the biological contaminants that Wright initially thought she’d be treating, using ultraviolet light. The end result is safe drinking water that also tastes good.

Earlier this year, Wright’s team won a grant from the United States Agency for International Development (USAID), enabling the researchers to test this system at full scale for the first time in New Mexico two months ago. A second stage of the grant will help bring a pilot to India this summer. Local farmers will use the system and provide feedback at a conference organized by Jain Irrigation, Inc., a company based in Jalgaon, India. Wright’s team is now looking to find out how easy it is for users.

The USAID competition was actually intended for systems built for individual farms, but Wright calculated that the amount of water used by a single farm is similar to the amount of water that a small village needs for its daily drinking water — 6 to 12 cubic meters. 

Although Wright’s work is currently focused on rural villages in India, she sees many uses for the technology in the United States as well. In isolated areas, such as the ranches in New Mexico where she tested her system at full scale, poor access to water pipelines often leads to a heavy reliance on well water. But some ranchers find that even their livestock won’t tolerate the saltiness of this water.

“It’s useful to install a small-scale desalination system where people are so spread out that it’s more costly to pump in water from a municipal plant,” she says. “That’s true in India and that’s also true in the U.S.”

Topics: Research, School of Engineering, Mechanical engineering, Students, graduate/postdoctoral, Water, Global, India, Alternative energy, International development, Solar, Profile


Natasha Wrigh,
Yes India had a problem,that what you have specify in the news.Even india have rivers but the people who are living near to sea shore not able to drink pure water because in contain Salty.I am doing Ph.D in control system application in power system in NIT Jamshedpur,Jharkhand.I am much very happy in helping you regarding villages drinking water.I Know the pain of drinking water in my village.
If you required any help from my side, i do it.

M S Dinesh
Research scholar,
NIT Jamshedpur,

Hi Natasha,
does your approach differ very much from this one:

Hi Natasha
Sid here, awesome work and congratulations. You have been working really hard and the efforts have paid off.
Congratulations on your achievement.

Looking forward to see you in India.

Wow, I experience this story as heart-warming and encouraging that we have what it takes to make the world a better place. Thank you Natasha, Amos and your team! :)

Go natasha!!!

Excellent work

You must look forward to Desal prize

Can you find a cost-effective method to desalinate sea-water?

That's pretty awesome stuff. Low-cost, low-scale desalinization would be really helpful in dry coastal areas as well.

Hi Natasa Wright
This is Dr.J.T.A.Chowdhury,working 23 years as Water Quality Expert in Bangladesh.30% in my country coastal area where people are facing problem salt water for drinking. They are using ground water for drinking purpose and some time surface water. Your device highly useful for this area. Most of the coastal are are remote area. It will be highly appreciated, if you piloting your device in my country.Huge number of people will be benefited and can save their life from saline water.
Best regards


Dear Ms Wright,
I am an Electrical and Electronic Engineer in India. Presently, I am working for 'Barefoot' NGO under 'Youth for India' fellowship of 'State Bank of India'.

The NGO is working towards increasing awareness in solar energy in rural India. For this, it is working in State of Rajsthan which is dessert, arid and dry region. The ground water in the villages is saline and is of no use.

I believe you all have done some pioneer work in the sector of desalination of water with the help of solar energy. Could you help me out in this regard. I am looking for a solar based system with low cost and maintenance which can be operated by villagers. As I am an engineer myself, initial installation and fabrication will not be a problem.
Thanks in anticipation of quick response.

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