Sunlight + Air = Sterile Water Supplies

Water DropsResearchers at the University of Hull (UK) reported that they have found a means to “produce constant supplies of sterile water, powered simply by sunlight and air.” The technology is specifically designed to be used in those areas where conventional water treatment systems, such that those that use chemicals or electricity, are not a viable option.

Dr. Ross Boyle, lead researcher on the project, says the system uses photoreactive molecules that produce a highly toxic form of oxygen. These molecules — known as porphyrins — were originally designed to attack cancer cells.

“We know from earlier work that the same technique which works on cancer cells will destroy many species of bacteria including MRSA and E. coli,” says Dr. Boyle in a news release redistributed by the PhysOrg website. “It can also knock out at least one common parasite. And a major advantage is that it doesn’t create resistance in micro-organisms.”

The porphyrins are attached to small glass beads, according to the researchers. These beads are packed inside a transparent tube, through which water flows. When water flows through this tube in sunlight, the porphyrins on the beads react and create the toxic form of oxygen. This, then, kills any bacteria and parasites in the water, sterilizing it.

Boyle says he already knows how to fix his molecules to a glass surface and is confident the production of the beads will be a straightforward process. He says:

The device needs to be very simple, low-cost and easy to transport in order to be a realistic and practical option for remote rural communities. No special materials beyond the glass beads will be needed; an up-turned plastic drinking bottle may even be enough to hold them. The beads won’t need refrigeration or special storage conditions, and will keep indefinitely if stored in the dark.

Used glass beads are the only byproduct from this system. The so-called toxic form of oxygen reportedly spontaneously and rapidly reverts to normal oxygen if it does not react with the microorganisms. The beads will reportedly have a set lifespan for their use. When they are completely used, they can either be recycled or reused. The light-sensitive molecules can be reapplied.

The academic researchers note that sterile water is particularly needed in those areas in which there is limited healthcare access. Sterile water is usually made with chemicals such as hydrogen peroxide or chlorine, or else, via ultraviolet treatment, which relies on electricity. Filtration systems are also of limited use and filters clog when there is debris or heavy particulates in the water.

Clean drinking water is not only a need in emerging nations, but the United States as well. Paul Gallay, president of Hudson Riverkeeper, writing for The Huffington Post, notes that William K. Reilly, who served as U.S. Environmental Protection Agency administrator in the George H.W. Bush administration, “warns that 117 million Americans still lack proper access to safe drinking water. And, as many as 3.5 million Americans are being sickened each year because of bacteria in poorly-treated wastewater.”

Boyle says his goal is to have a working prototype of the system available in “a few months.” Then, he will determine factors to optimize its use, including finding how long the treated beads are effective. Ultimately, the device will be tested in field trials in South Africa. The research is funded by the Sir Halley Stewart Trust.

Image by uniccus, used under its Creative Commons license.