PATHOGEN REMOVAL USING MORINGA OLEIFERA MODIFIED SAND COLUMNS FOR POINT-OF-USE WATER PURIFICATION

Open Access
Author:
Wang, Ziyuhan
Area of Honors:
Environmental Engineering
Degree:
Bachelor of Science
Document Type:
Thesis
Thesis Supervisors:
  • Stephanie Butler Velegol, Thesis Supervisor
  • John Michael Regan, Honors Advisor
Keywords:
  • water purification
  • Moringa
  • Sand Column
  • pathogen
  • wastewater
Abstract:
As billions of people in developing regions have limited access to safe drinking water sources, it is apparent that more affordable and available water purification methods are needed. Developing a drinking water treatment device with Moringa oleifera seeds enables a locallysourced and less expensive alternative to traditional water purification methods in developing world. 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. 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 pathogen, E. coli, than bare sand columns. Previous series of f-sand column experiments using microspheres suggests the particle removal and column lifetime can be predicted using the Clean Bed Filtration theory. This f-sand filter demonstrated ∼4 log removal of 1 μm polystyrene particles and >8 log removal of Escherichia coli compared to <0.1 log removal for bare sand. 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 does not reach breakthrough until 100 pore volume of the column. Regeneration tests of f-sand columns after breakthrough, and column tests using lower influent concentration to mimic the real-life wastewater situation will be performed.