Tropical tree seeds provide sustainable water filtration

Researchers have designed a simple drinking water filtration method using sand combined with a protein extract from the seeds of the Moringa oleifera tree, common in equatorial regions. Moringa seeds contain positively charged, water-soluble proteins that have been found to attract particles and kill bacteria. Stephanie Butler Velegol and Manish Kumar of Pennsylvania State University and their colleagues suspended ground-up Moringa seeds in water and then combined the liquid extract with sand. The researchers packed the sand into filter columns about 1 cm in diameter by 5–10 cm high and carried out tests to optimize the columns’ performance. The filters completely removed Escherichia coli from water in which the concentration of the bacteria was more than 100,000 times as great as that in typical wastewater samples (Environ. Sci. Technol. Lett. 2017, DOI: 10.1021/acs.estlett.7b00490). The researchers aim to develop the design into an easy, inexpensive, and sustainable way for households and communities in the developing world to clean water for drinking.