The United Nations reports that, according to the Millennium Development Goals Report 2012, 783 million people (11 percent of the global population) do not have access to an improved source of drinking water. These sources include household connections, public standpipes, boreholes, protected dug wells, protected springs, and rainwater collections. Over 40 percent of all people without improved drinking water live in sub-Saharan Africa.
The problem of insufficient water is not limited to Third World countries. An Al Jazeera America article states that communities such as California’s San Joaquin Valley, Appalachia, and Alabama’s Black Belt are suffering from a lack of clean water. The article states that “The Alabama Department of Public Health estimates 40 to 90 percent of households have either inadequate or no septic system and of the systems that have been installed, half are failing.” Doctors in Alabama have reported treating patients who suffer from intestinal worms, hepatic cysts from parasites, and hookworm.
So, how do we solve this problem? Nanotechnology may hold the answer.
A January 2015 paper in Nanotechnology, Science and Applications entitled “Innovations in nanotechnology for water treatment” states that “Nanoengineered materials, such as nanoadsorbents, nanometals, nanomembranes, and photocatalysts, offer the potential for novel water technologies that can be easily adapted to customer-specific applications. Most of them are compatible with existing treatment technologies and can be integrated simply in conventional modules. One of the most important advantages of nanomaterials when compared with conventional water technologies is their ability to integrate various properties, resulting in multifunctional systems such as nanocomposite membranes that enable both particle retention and elimination of contaminants. Further, nanomaterials enable higher process efficiency due to their unique characteristics, such as a high reaction rate.”
However, the paper continues, “there are still several drawbacks that have to be negotiated. Materials functionalized with nanoparticles incorporated or deposited on their surface have risk potential, since nanoparticles might release and emit to the environment where they can accumulate for long periods of time. Up until now, no online monitoring systems exist that provide reliable real-time measurement data on the quality and quantity of nanoparticles present only in trace amounts in water, thus offering a high innovation potential. In order to minimize the health risk, several national and international regulations and laws are in preparation. Another more technical limitation of nanoengineered water technologies is that they are rarely adaptable to mass processes, and at present, in many cases are not competitive with conventional treatment technologies. Nevertheless, nanoengineered materials offer great potential for water innovations in the coming decades, in particular for decentralized treatment systems, point-of-use devices, and heavily degradable contaminants.”
A chemical engineer from Tanzania has developed a specialized water-filtration system to help combat these issues. Dr. Askwar Hilonga, a post-doctorate at Hanyang University and a lecturer for The Nelson Mandela African Institution of Science and Technology, has developed a sand-based water filter that cleans contaminated drinking water using nanotechnology. Each Nanofilter is engineered for a specific body of water and absorbs the contaminants present — from heavy metals or minerals, such as copper and fluoride, to biological contaminants like bacteria and viruses, along with pollutants such as pesticides.
The innovation earned him the first Africa Prize for Engineering Innovation, an initiative of the U.K.’s Royal Academy of Engineering. It encourages talented sub-Saharan African engineers from all disciplines to develop solutions to local challenges, and to develop them into businesses. Dr. Hilonga’s innovation earned him prize money of over $38,000. After an impressive 33 academic publications, Hilonga’s trademarked Nanofilter is set for commercialization within a year, and could change the lives of thousands of Africans.
The University of Twente’s MESA+ Institute for Nanotechnology is also working with nanotechnology to provide clean water. Harmful nitrate in drinking water — nitrate, caused by excessive use of fertilizers, contaminates groundwater which may then enter the main water supply — can be removed by catalyzing its conversion to nitrogen. This process suffers from the drawback that it often produces ammonia. By using palladium nanoparticles as a catalyst, and by carefully controlling their size, this drawback can be eliminated. Using palladium to catalyze the conversion of nitrate to nitrogen speeds up the process enormously; however, it produces ammonia, which is a harmful by-product. The amount of ammonia produced depends on the method used to prepare the palladium and on the catalyst’s physical structure, so researchers use nanometer-sized colloidal palladium particles since their dimensions can be easily controlled. These particles are fixed to a surface and therefore don’t end up in the main water supply. Since it’s vital to keep them from clumping together, stabilizers like polyvinyl alcohol are used – however, these stabilizers tend to shield the surface of the palladium particles, which reduces their effectiveness as a catalyst. The researchers introduced additional treatments to fully expose the catalytic surface once again or to manipulate it in a controlled manner. This has resulted in palladium nanoparticles that can catalyze the conversion to nitrogen, while at the same time producing only a little ammonia.
As organizations and individuals continue their research for ways to provide clean water, the United Nations is also working toward this goal. In July 2010, the General Assembly recognized the right of every human being to have access to sufficient water for personal and domestic uses (between 50 and 100 liters of water per person per day), which must be safe, acceptable, and affordable (water costs should not exceed 3 percent of household income), and physically accessible (the water source has to be within 1,000 meters of the home and collection time should not exceed 30 minutes). The U.N.’s Millennium Development Goals Report 2012 includes a water-related target that outlines its ambitions for the future. The world has met the MDG drinking water target five years ahead of schedule — in 2010, 89 percent of the world’s population was, up from 76 percent in 1990. If current trends continue, 92 percent of the global population will be covered by 2015.
