Purpose: Here we study the effect of ZVI incorporation in sand filtration columns on the removal of Tulane virus (TV) and murine norovirus (MNV) from an aqueous system.
Methods: TV and MNV suspensions (100 ml at 103 to 104 RT-qPCR units) were loaded separately onto each of two columns (~130 cm3 volume; 45-ml pore volume) of sand alone and a 1:1 ratio of sand:ZVI (particle size 0.005 to 0.125 in). Viral suspensions and a subsequent flush of sterile deionized water (300 ml per column) were pumped through the columns at a rate of 1 ml/min. Eighty 5-ml fractions of eluate were collected beginning five minutes after input. Every fifth fraction was tested for viral RNA by RT-qPCR. Two trials were conducted for each virus.
Results: MNV was detected throughout collection of the eluate from the sand column with a peak of over 103 RT-qPCR units at the beginning of the flush period. Fewer than 10 RT-qPCR units of MNV were recovered at any point during eluate collection from the ZVI:sand column. TV (average 20 RT-qPCR units at peak) was detected from eluate of the sand column. However, TV was not recovered from the ZVI:sand column eluate for the first trial, but was recovered in the eluate in the second trial comparable to the sand column.
Significance: Incorporation of ZVI in sand filtration systems may aid the removal of virus from water systems with potential application for enhanced safety of drinking and irrigation water. Comparison of the significant removal (P < 0.05) of both surrogates provides evidence for interaction of the viral capsid with ZVI.