Clean water can ‘grow’ on trees

Scientists have known for a while about the water-purifying properties of seeds from Moringa olfeira, the so-called “miracle tree” that’s native to northwest India but can grow in many other parts of the world. But past approaches to using the seeds to remove disease-causing microbes from drinking water have proven too complicated and expensive.

New research from chemical engineers at Pennsylvania State University, though, has identified a simpler and more affordable way to harness Moringa’s purification powers.

The secret, according to Stephanie B. Velegol and her colleagues, lies with adding an extract from the seeds — which contains a positively charged protein — to negatively charged sand. The resulting “functionalized sand,” or “f-sand,” not only helps to kill bacteria in water but helps to remove them as sediment.

The process makes it possible to produce clean, storable water for drinking using just seeds and sand.

One problem with previous methods for using Moringa seeds is that, used alone, the seeds also release other proteins and organic matter into the water. Those materials can eventually encourage new pathogens to grow, preventing the ability to store the treated water safely for later use. The new method of adding sand eliminates that concern by depositing the proteins on sand, which can then be removed through a rinsing process.

“Overall, these results open the possibility that (f-sand) can provide a simple, locally sustainable process for producing storable drinking water,” the researchers write.

Currently, some one billion people across Asia, Africa, and Latin America rely on untreated surface water sources for their daily drinking and cooking needs. An estimated two million people — most of them children under the age of five — die from water-borne diseases every year.

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