7 Log Virus Removal in a Simple Functionalized Sand Filter

Viral contamination of drinking water
due to fecal contamination
is difficult to detect and treat effectively, leading to frequent
outbreaks worldwide. The purpose of this paper is to report on the
molecular mechanism for unprecedented high virus removal from a practical
sand filter. Sand filters functionalized using a water extract of Moringa oleifera (MO) seeds, functionalized sand
(f-sand) filters, achieved a ∼7 log10 virus removal.
These tests were conducted with MS2 bacteriophage, a recognized surrogate
for pathogenic norovirus and rotavirus. We studied the molecular mechanism
of this high removal since it can have important implications for
sand filtration, the most common water treatment technology worldwide.
Our data reveal that the virus removal activity of f-sand is due to
the presence of a chitin-binding protein, M. oleifera chitin-binding protein (MoCBP) on f-sand. Standard column experiments
were supported by proteomic analysis and molecular docking simulations.
Our simulations show that MoCBP binds preferentially to MS2 capsid
proteins demonstrating that specific molecular interactions are responsible
for enhanced virus removal. In addition, we simplified the process
of making f-sand and evinced how it could be regenerated using saline
water. At present, no definitive solution exists for the challenge
of treating fecally contaminated drinking and irrigation water for
viruses without using technologies that demand high energy or chemical
consumption. We propose functionalized sand (f-sand) filters as a
highly effective, energy-efficient, and practical technology for virus
removal applicable to both developing and developed countries.