The Earth’s population is booming, the planet is getting hotter, and drinkable water is either scarce or contaminated in many parts of the world. While certain commercial water purification methods depend on non-sustainable methods and materials that are environmentally taxing, there are great alternatives. Natural water filtration systems can remove bacteria, sediment, and protozoa from fresh water just as well as commercialized systems and are more accessible to people in parts of the world where resources are scarce.
The gooey core inside cactus leaves, called mucilage, has been known to remove sediment from water for ages, yet research is finding it also can also remove arsenic and bacteria. Boiling the mucilage with contaminated water creates a floating film that can easily be skimmed, creating safe and drinkable water for people in need. The technology was successfully tested during the 2006 Haiti earthquake, where displaced people needed clean, potable water.
Certain varieties of tree branches can make for a simple purification technique. MIT researchers found that xylem tissue from a white pine tree, when used to filter contaminated water, removed 99 percent of E. coli bacteria. The very same tissue that delivers life-giving sap to all parts of the tree also traps bacteria. Using this technique in parts of the world where resources are scarce can still produce safe, purified water in a pinch.
For those in tropical areas of the world, fresh water may already be scarce. Luckily, this is where the Molinga Oleifera tree, a drought-resistant plant whose seed contains a protein that binds to pollutant particles, flourishes. Researchers perfecting the technique are communicating with the governments of Namibia and Botswana, among other nations, who could benefit from having a reliable method of decontaminating water.
Many commercial water purification ventures use activated carbon to do the job, yet some areas have naturally occurring “bioabsorbent” plants that are much more readily available and cheap. Cilantro leaves do so well at removing pollutants – even toxic metals such as lead – that a bunch of the herbs can be used as a replacement filter for commercial purification systems.
Arsenic is known to poison groundwater in at least 70 different countries, so scientists have been scrambling to find the perfect chemical solution to combat the hazard. A more natural approach uses the symbiotic relationship of a certain bacteria and algae to safely filter arsenic from drinking water. The bacteria converts arsenic into a less toxic and less soluble form so it can be more easily removed, while the algae provides a reliable supply of carbon. Carbon dioxide from the bacteria’s processing, in turn, feeds the algae in these innovative filters.
UNICEF and the Water Sanitation Program received accolades for providing Cambodia with ceramic water filters, a purification system that reduced the country’s prevalence of diarrheal diseases by 50 percent. The porous nature of ceramic prevents nearly all bacteria and protozoa from reaching the water supply, specifically reducing E. coli by 99 percent. Gravity is all that is needed to get the system going, which is perfect for areas that require simple and easily accessible solutions.