A simple, inexpensive, easy-to-use device developed over the past six years at the University of Virginia has the potential to make safer drinking water a reality for millions.
The water-disinfecting device is a ceramic tablet known as the MadiDrop, created in the lab of Dr. James A. Smith of the School of Engineering and Applied Science and produced by a nonprofit founded with support from UVA’s Licensing and Ventures Group. The original version is already in use in thousands of households in 40 countries.
This summer, however, with the release of the new MadiDrop+, along with the launch of a for-profit company to help expand production and distribution, Smith hopes that the tablet could soon become far more widely available to the hundreds of millions of people worldwide who lack access to clean water.
Small enough to fit into a pocket, the MadiDrop is remarkably simple. When the silver-infused ceramic block is placed in water, it releases silver ions that are highly effective against a broad spectrum of microbial pathogens such as E. coli, shigella and Vibrio cholerae, and moderately effective against cryptosporidium and giardia as well as viruses like rotavirus and adenovirus—all contaminants that can cause serious and potentially deadly diarrheal illnesses. The original MadiDrop, first released in 2016, is effective for about six months; the new MadiDrop+ can treat up to 20 liters of water a day for an entire year—or more than 7,000 liters of water—at a cost of $6 per tablet.
Smith became interested in the issue of clean-water access during a sabbatical year in the early 2000s, while developing a civil engineering class called Water for the World that he still teaches at UVA. What he learned about the global health impact of poor water quality, Smith says, “really shifted my research focus to include work on developing-world water and coming up with appropriate and sustainable solutions for that problem.”
According to the World Health Organization, 600 million people worldwide rely on water from unprotected wells, springs or surface-water sources such as streams and lakes. Each can be contaminated with a wide range of intestinal pathogens, such as coliform bacteria, that can cause serious and potentially deadly diarrheal illness. Exposure to intestinal pathogens is particularly harmful to young children; of the more than 500,000 deaths each year from diarrheal illnesses, most are children under 5.
But repeated exposure to these types of pathogens can also take a more insidious toll on child health, explains Dr. Liz Rogawski McQuade. As assistant professor in the school of medicine’s division of infectious diseases and international health, Rogawski McQuade is studying the MadiDrop’s use in households in South Africa. Especially in a child’s first two years of life, she says, a “vicious cycle” of infection, illness, malnutrition and other health problems can lead to stunted growth, impaired cognitive development and “long-term poor outcomes.”
In search of viable solutions, Smith first focused on an existing technology that has been in use for several decades: pot-shaped ceramic filters made from clay and sawdust and painted with silver. While effective, Smith says, the pots have drawbacks, including weight and cost, that limit their practicality for widespread implementation. With those shortcomings in mind, Smith imagined a much simpler device: a ceramic block or tablet embedded with silver that could be dropped into a standard, covered water-storage container. “That was really the genesis of the MadiDrop,” he says.
Early versions of the MadiDrop, developed by researchers in Smith’s lab, demonstrated the viability of the idea. One change to the MadiDrop before it was officially introduced made it small enough to fit into the mouths of a wide variety of water-storage containers. Researchers also developed a now-proprietary process to ensure that the tablet reliably disinfects and keeps silver levels in the water well below the recommended safety limits.
In the study now being conducted in South Africa (a collaboration between researchers at UVA and the University of Venda), data gathered so far, according to Smith and Rogawski McQuade, suggest that the original MadiDrop is working effectively in actual households under real-world conditions.
Into the future
This summer’s launch of the for-profit Silivhere Technologies Inc. will make it possible to seek investment capital to help meet the next challenge: increasing production and bringing the MadiDrop+ to more people.
Smith hopes that major aid agencies will adopt the MadiDrop for humanitarian distribution to the world’s poorest people. He also sees enormous commercial potential in the growing class of more affluent consumers in places such as India, where even tap water still often can be contaminated.
Expanding into these new markets represents a “formidable challenge,” Smith says. “But if we can be successful, we’ll have done a lot of good, and we’ll have helped a lot of people have safe water.”