Raising the Bar in Water Purification with Nanotechnology


Puralytics_solarbag The World Bank reports that over 88% of worldwide illness is related to contaminated water. An Oregon-based company has successfully produced a highly effective personal water purification system that could be of massive benefit to humanitarian relief efforts. The Solar Bag, developed by Puralytics, boasts the ability to not only filter, but truly purify water of up to 99.999% of contaminants using the sun. The company is currently partnered with GS Malawi, an organization working in Bolero and Mzuzu regions of the country, to empower residents through access to safe drinking water. They are delivering Solar Bags to those participating in their programmes and are reducing thirst and increasing health along the way.

Solar technology for filtration is not an entirely new concept. Various kinds of Solar Water Disinfection Units (SODIS) have been around for a while, however none are able to physically purify water of contaminants like the Solar Bag does. In fact, it is able to rid heavily contaminated (or highly turbid) water of bacteria, viruses, protozoa, pesticides, herbicides, petrochemicals, pharmaceuticals, arsenic, and heavy metals like lead and mercury. It uses a mesh coated in specific nanotechnological layer to destroy water-borne contaminants. The sun activates five photochemical processes that use solar radiation to bond toxins and kill micro-organisms.

Unlike traditional filters, the Solar Bag completely purifies via a photo-catalytic process. Most SODIS utilize clear plastic, and rely on sun and the heat it generates to destroy some pathogens or inactivate them. Filters using this technology were unable to catch viruses, various strains of bacteria, or chemicals like pesticides because they were too small and they slipped through the filtering mechanisms. The Solar Bag destroys the pathogens and chemicals by breaking them apart. The result is perfectly clear, disinfected, and detoxified water that far surpasses the US EPA and World Health Organization regulations.

solarBagDiagramThe SODIS method generally takes 6-12 hours in full sun to filter heavily contaminated water. The Solar Bag takes between 2-3 hours on a sunny day, and 4 – 6 hours if it’s cloudy. For cloudy days, a PurBlue Process Timer is included. A drop of blue liquid will let you know when it’s ready. It can filter up to 9 litres of water per day, can be reused up to 500 times, and can be stored for 7 years. Relief agencies during humanitarian crises often have to ship drinking water during the initial phases of relief. One gallon of water equates to roughly 8 pounds. One Solar Bag can produce upwards of 500 gallons over its lifetime. Using this tool, agencies would save money and be able to divert those funds to other relief efforts.

In 2012, Puralytics distributed 114 Solar Bags to its partners in Malawi and conducted a 6 month trial. During this period, people used the bags 1 – 2 times per day. 82% said they willingly drank much more water, 89% reported being sick less often, and 91% boiled water far less often, which meant that people were stronger and healthier, had more time for other tasks and spent less on fuel. Puralytics is currently engaged with a number of organizations, both local and international and are working to provide upwards of 5000 to people in Africa, via small business ventures. At present, the Solar Bag has been shipped to upwards of 50 countries globally, and has been utilized and distributed by the Red Cross, Medical Teams International, Relief International, and Forward Edge International.

Puralytics_redcross_philippinesIt was included in NFI kits as part of the recent Haiyan relief effort and was distributed to government agencies, emergency response teams and aid and relief agencies. Some were donated, some were purchased. In its partnership with GS Malawi, its business model is buy one, get one. A bag retails for about $80 but all NGOs receive discount rates.

While the Solar Bag is perhaps best marketed to NGOs and other agencies that can bear the cost, Puralytics has another innovation in mind that may be more accessible to residents in the Global South. Puralytics has patented its nanotechnology photochemical water purification process and is applying it to a range of other products to promote sustainable water usage. The “LilyPad” is a scaled up version of the SolarBag, meant to float in a pond or other contaminated body of water. It is currently undergoing testing but, if successful, may be made available to small villages as a communal alternative source of clean water. The company has also developed purification systems for wells, which can purify up to 500 gallons per day.

The Solar Bag has won a number of awards, including the National Grand Prize at the CleanTech Open and the International Water Association Global Honor Award. The company was named one of the top 50 water tech companies by Artemis Project and is one of the Global CleanTech 100.

For more information about the company and its work visit its website or listen to Mark Owens, founder of Puralytics, explain how the Solar Bag works and its application for development below:


Sarah Anstett

Sarah Anstett

Sarah is a writer, researcher, and development practitioner currently based in Toronto, Canada.

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