Over two billion people on the planet lack access to adequate sanitation. That means dirty water, disease, and contaminated medical supplies. Without access to proper infrastructure providing plumbing or electricity, finding a way to create and bring off-the-grid technology to areas of the developing world has proven to be a substantial challenge. A team of engineers at Rice University have captured the power of the sun to invent solar steam sterilization unit that uses light-absorbing nanoparticles that can power autoclaves and sanitize human waste. The project has been awarded a grant by the Bill and Melinda Gates Foundation as a part of their efforts to improve the living conditions of the world’s poor.
The solar steam system functions by using nanoparticles to soak up the sun. They nanoparticles heat up surrounding water quickly, causing it to vaporize into steam. The process can even work when the water is ice-cold, boasting an overall efficiency of 24 percent as compared to solar panels which only operate at an efficiency of 15 percent. While it is possible to generate electricity this way, the researches decided to first focus on the problem of sanitation. It was tested with two other structures, one that was able to sterilize medical and dental equipment, and the other to treat human waste. The system can handle the contributions of a family of four with only two applications a week.
“Sanitation technology isn’t glamorous, but it’s a matter of life and death for 2.5 billion people,” says the director of Rice’s Laboratory for Nanophotonics (LANP) Naomi Halas. “For this to really work, you need a technology that can be completely off-grid, that’s not that large, that functions relatively quickly, is easy to handle and doesn’t have dangerous components. Our Solar Steam system has all of that, and it’s the only technology we’ve seen that can completely sterilize waste.”
The group is looking to partner with Sanivation, a waste treatment company in order to conduct field tests in Kenya. Taking into account the resources available, the solar system can save lives by eliminating dangerous pathogens with the power of steam.