Intelligent Design: Bishop’s student makes, patents water purification system

After seven months in development and years of passion on water issues, Bishop’s School senior Sayeh Kohani, 17, has created what she calls the SolarSave water purification system. On July 27, the patent for her invention cleared and she received a prototype. This November, Sayeh will travel to Ethiopia to deliver as many units as she can to villages in need of clean water.

The complete system is a two-foot-by-two-foot acrylic box, which can be half filled with polluted water and topped with a buoyant fit-to-size, carbon-coated, foam and fabric appliance. The appliance uses the power of the sun to heat the water and converts the water to steam, which re-condenses in a chamber into desalinated, purified, pathogen-free water. Sayeh reports the SolarSave system produces 12 liters every 24 hours.

“It’s time for us to prioritize water. It makes me angry and kind of disappointed that a water crisis that affects millions of people hasn’t been fixed. But it’s a complicated problem and it’s going to take infrastructure, which will take decades to make. In the meantime, I hope SolarSave can help a lot of people who don’t have access to clean water,” she said. “Cholera, typhoid, hepatitis are all diseases traced to polluted water. In parts of Africa and Asia, they don’t have irrigation systems. Their water comes from rivers that contain runoff because people empty their defecation containers (into the river water) and then people drink it.”

When it came to developing the SolarSave system, each step was carried out with knowledge-based decision making.

It all started with her participation in The Bishop School’s Model UN program (but Sayeh’s parents say her interest in water issues began when she was a small child, doing essays on water shortages in fifth grade). “One year I was on the World Heath Committee of Model UN and the topic was water-borne diseases. It’s the 21st Century, you wouldn’t think water could cause so much damage, but we found that water … causes 3.4 million deaths a year. That’s horrific,” she said.

With a pre-existing interest in science and public health, Sayeh set out to create a water purification system that is cost-effective, easy to produce and self-sustaining.

First, came the generator

“I knew from the start the product could not have a power source because most of the affected regions don’t have access to electricity. So the obvious choice for me was using the power of the sun. But the problem with solar panels is they are expensive and difficult to transport, so they wouldn’t be efficient or effective,” she explained.

Seeking alternatives, she did research into the power of carbon and how it could doubly harvest solar power and purify water. Carbon is often used in at-home water purification systems such as Brita filters.

“I work at The Scripps Research Institute and they use these mesh wipes called Berkshire Cleanroom Wipe Durx 670 to clean the rooms. If you dab water on a corner, it draws it up so quickly. I thought of coating the fabric in carbon powder to heat and purify the water,” she said. “Because of the carbon, when the bottom of the appliance gets wet, it is black as can be, and able to absorb sunlight really efficiently and raise the temperature to around 100 degrees Celsius. The appliance sits in the polluted water and the fabric draws up the water, heats it up and generates steam.”

The fabric is woven in an undulating pattern through slits in the foam to keep it afloat. It’s able to draw-in water without becoming completely submerged. The foam appliance would last for two years before it would need to be replaced. But given the availability of materials, Sayeh said they could be built easily and cheaply (the Berkshire Cleanroom wipes can run as low as 15-cents each).

Then came, the container.

Sayeh said she needed to find a sturdy, clear material (so the sun could get through) that would be inexpensive and wouldn’t turn yellow. After some brief research, she decided on clear acrylic and sent out designs for a prototype.

When it arrived July 27, she immediately put it to the test. In a demonstration for La Jolla Light, she showed how the lid easily comes off, the lightweight foam/fabric appliance comes out, and dirty water goes in the basin, topped with the appliance. Within minutes of being outside — despite a cloudy day — the lid began to steam.

“You could take water from any source and refill it whenever you need to. Steam is the best way to distill water; not only does it get rid of pathogens, but it desalinates as well. So if people live near an ocean or a sea body, they could use this,” she said.

Now, on to fundraising

Next, Sayeh said she would like to raise funds because she plans to make 150 SolarSave water purification systems by Thanksgiving and take them to Africa to distribute. She said a website and donation page will go live as soon as it’s developed.