solar-powered water purifier
Recently, scientists at Stanford University and the Department of Energy’s SLAC National Accelerator Laboratory have developed a tiny, solar-powered water purifier resembling a rectangular bit of black glass. The new device does not have a name yet, but is being referred to as a “tablet.”

Access to safe drinking water is a problem for 663 million people in the world. The World Health Organization reports that unsafe water supplies, sanitation and hygiene are responsible for 842,000 deaths every year, 361,000 of which are children under the age of 5.

What sets this device apart from other water purifying gadgets on the market is its use of a wider range of light. According to the Global Citizen Organization, the device absorbs 50 percent of incoming sunlight energy, while other purifiers only absorb 4 percent.

According to project leader Chong Liu, “This can greatly enhance the speed of water disinfection. It does not need any additional energy or effort for treating water.” In an experiment, the tablet took only 20 minutes to function. In contrast, other purifying systems that use only UV rays can take up to almost 48 hours.

On the surface of the tablet is a layer of nanoflakes and a small amount of copper. The nanoflakes’ exposure to sunlight and water excites electrons in the device and results in the release of hydrogen peroxide. This chemical kills bacteria in the water, making it safe to drink. As of now, however, the tablet is only capable of killing E. coli and lactic acid bacteria.

In an experiment published in the Nature Nanotechnology journal, researchers placed the solar-powered water purifier in a container with 25 milliliters of water for 20 minutes. It killed 99.99 percent of the bacteria in the water, an impressive amount for such a short amount of time. Even Liu said, “We didn’t expect it to work that well at first.”

Since the device is new and not ready for the market yet, it has no fixed price. But according to Liu, “The material itself is cheap and the synthesis process is facile. So we assume that the device would be of low-cost.”

More experiments and field tests must be done before the tablet can be distributed. Nonetheless, this solar-powered water purifier has the potential to cheaply and quickly help people who struggle to obtain clean drinking water.

Karla Umanzor

Photo: Flickr

Life-SackApproximately 63 million people do not have access to clean water, according to the World Health Organization (WHO). To address this problem, industrial designers Jung Uk Park, Myeong Hoon Lee and Dae You Lee came up with the Life Sack.

The Life Sack functions as a water purifier that utilizes solar water disinfection process (SODIS) technology. UVA radiation and thermal treatment work together to kill toxic microorganisms and bacteria.

Typically, UVA radiation and thermal treatment are individually harmful to microorganisms and bacteria. The combined effect, therefore, increases the efficacy of the purification process. Moreover, the polyvinyl chloride (PVC) composition lends the Life Sack a high sunlight penetration ratio and durability.

Fashioned as a backpack, the Life Sack also ensures ease of mobility, which is especially crucial for areas without sources of water. These areas rely on individuals to travel outside of the community to supply the water that they need.

Water purification is not the only way that the Life Sack can be used.

The designers were partly inspired by how nongovernmental organizations and other charities often sent their supplies, such as grain and other food staples, in sacks. The Life Sack can thus double as a storage unit, allowing users to easily store and transfer goods other than water when needed. According to CauseTech, some nongovernmental organizations now use the Life Sack rather than “conventional food bags” to send their goods.

Since the initial launch of the Millennium Development Goals (MDGs), great improvements have been made in global access to improved sources of drinking water. From 1990 to 2015, the percentage of the global population with access to improved sources of drinking water has risen from 76 percent to 91 percent.

Further improvements are still to be made. Of the 63 million without access to clean water, most are concentrated in Sub-Saharan Africa and Southern and Southeast Asia.

A lack of access to clean water increases the propensity for water-borne diseases. Figures from WHO indicate that 760,000 children under five die of diarrheal diseases every year. More universal access to clean water would help in reducing this number.

Goal six of the United Nations’ 2015 Sustainable Development Goals (SDGs) addresses the need to “ensure access to water and sanitation for all” by 2030. Innovations like the Life Sack may support this effort toward increasing global access to improved water sources.

Jocelyn Lim

Sources: Inhabitat, SODIS, Tuvie, The United Nations, UNICEF

NanotechnologyClean drinking water is one of the most basic needs for humans, yet almost 783 billion people worldwide do not have access to it. Each year an estimated 6 to 8 million people die globally as a consequence of water-related diseases. These statistics reinforce the absolute necessity that is clean drinking water and the devastating results of inaccessibility to this necessity.

The suitability of water for human consumption requires that the water not only not be turbid but be free from toxins as well. Turbidity refers to the loss of transparency in the water due to visible impurities while toxins, which must be removed, are chemical secretions of organisms — particularly bacteria and fungi — that cause disease.

To make water sanitary for drinking needs, both of these impurities require proper expulsion from the water source. Many of the traditional techniques of purifying water focus exclusively on one kind of impurity. For example, the chlorination method can only kill microorganisms, whereas filtration can only remove sizable impurities. However, nanotechnology might be able to do both.

Today, the use of nanoparticles has revolutionized industry, from nanoparticle-coated bandages to food containers. Nanotechnology is essentially the application of nanoparticles, particles ranging from 1 to 100 nanometers in size. These particles can be of various species: pure metals like silver, metal compounds like zinc oxide or even nonmetals like carbon and silicon.

As in other fields, nanoparticles have a part in purifying contaminated water. Nanoparticles of varying sizes and chemical properties are being used to rectify both turbidity as well as microbial toxins. The usefulness of the nanoparticles depends on their size-to-area ratio, which magnifies the chemical as well as physical properties of the substance the nanoparticle is made of.

The use of nanoparticles such as carbon nanotubes and graphene rely on this increased surface area of the nanoparticle to maximize the adsorption of heavy metal ions as well as other pollutants. Many metal nanoparticles such as iron — which is currently being used on commercial levels for water treatment purposes as well – can function in the same way as carbon adsorption by forming bimetallic couples with inorganic, heavy metals in the water.

Additionally, the chemical reactivity of the nanoparticles is enhanced by the increase in the metal’s surface area. Nanoparticles, such as titanium, employ this quality to remove pollutants. Chemically reactive nanoparticles are being used to remove micro pollutants by changing the pollutant into an innocuous form through redox reactions.

Another major use of nanoparticles is in the removal of microbes. The presence of microorganisms such as bacteria and fungi can lead to buildup of microbial toxins. These toxins can lead to serious diseases, such as diarrhea and cholera.

Nanoparticles can combat these problems, by first killing harmful microbes and then by neutralizing the effects of the toxins. Silver nanoparticles are known for their antimicrobial properties. The presence of silver causes fatal DNA mutations in the microbes. The use of desalinating nanoparticles of carbon can also cause microbial cell death by disrupting the cellular osmotic balance. Both these approaches eliminate harmful microorganisms from water. Moreover, nanoparticles such as titanium oxide can react with toxins from microbes, which results in degradation of the toxin to a harmless chemical.

These attributes and a wide range of possible applications make the usage of nanoparticles for the purposes of water purification very promising. However, researchers need to carefully weigh the safety of nanoparticle-treated water intake as well as potential environmental consequences against the prospective benefits of nanotechnology.

– Atifah Safi

Sources: UMExpert, Elsevier, NCBI, USGS, Nanoiron
Photo: O Exotextiles

water purification
While NGOs and governmental organizations often lead the charge in the fight for clean drinking water, one Indian teenager is leading the way on her own.

The teenager is a 16-year-old girl named Prakriti Singh.

“After my grandfather died of jaundice and certain reports about water contamination in Delhi, I toured interiors of Bihar studying water scarcity and contamination issues,” she said in an interview with the Press Trust of India. “But it wasn’t feasible for me to work there, hence I decided to start with Delhi.”

She said that more than 200 families living in Madanpur Khadar consume unsafe drinking water. Because of this, she sent water samples to a laboratory for analysis.

To raise the necessary funds for the purification system, Singh baked and sold cakes. She obtained some money in donations from companies who responded to her requests.

Thanks to the helping hand of Project Why, an NGO with experience in the area, a local school became the home of the water purification system. The system is an Aqua Pristine RO 250 LPH and it can purify some 1,500 liters of water daily.

According to Singh, both families and students of the school maintain access to the clean drinking water. Because of the educational deficiencies with respect to water awareness in the area, Singh decided to appoint “water ambassadors” throughout the school. The ambassadors help to inform the population about clean drinking water.

Since the installation, Singh has helped to install another purification system. She intends to install another one in the future.

India, which has a population of over 1.2 billion people, is one of the fastest growing countries in the world. However, in a country where diarrhea, hepatitis and typhoid kill on a regular basis, maintaining access to legitimate water sources is key to a healthy population.

Ethan Safran

Sources: The Hindu, CIA
Photo: electropolishing