Pathogen Removal in Moringa Oleifera Modified Sand Columns

As billions of people in developing regions have limited access to safe water sources, it is apparent that more affordable and available water purification methods are needed. Current water treatment methods are often expensive, manufactured from foreign materials, or unaccepted by local communities. Moringa oleifera trees grow rapidly in equatorial regions around the world, and their seeds contain an antimicrobial cationic peptide (MOCP) that kills bacteria by fusing cell membranes. Developing a drinking water treatment device with these seeds enables a locally-sourced and less expensive alternative to traditional water purification methods in developing world. After adsorbing MOCP onto sand through a simple mixing and rinsing procedure, the Moringa-functionalized sand (f-sand) carries positive charge of +20 mV, with much less organic residues in the material compared to the conventional flocculating method. The f-sand can then be packed in sand columns that can achieve higher removal of particles with similar size to pathogens, than bare sand columns. A series of f-sand column experiments using microspheres suggest the particle removal and column lifetime can be predicted using the Clean Bed Filtration theory. F-sand column achieved 6 log removal of fluorescent E.coli using plate counting techniques. Fluorescent E.coli cells were adsorbed onto f-sand after filtration, visualized by fluorescent microscopy, in comparison to no bacteria being adsorbed onto bare sand. Preliminary data indicates f-sand filter do not reach breakthrough until 100 pore volume of the column. Future tests are to determine viability of attached bacterial cells, removal of bacteriophage, and regeneration of f-sand column after breakthrough.