In one embodiment, the present disclosure provides fail-safe mechanisms
for final filters. The fail-safe mechanisms of the present disclosure
include a prefilter that is essentially transparent or translucent to TOC
contaminants and a microporous filter downstream from the prefilter that
filters contaminants by means of size-exclusion, mechanical interception,
coagulation, or a combination thereof, the filter being adapted to
significantly reduce fluid flow and undergo blockage under a challenge by
TOC contaminants. In another embodiment, the present disclosure provides
a method of filtration that includes the steps of providing a microporous
filter disposed upstream from a final filter, the microporous filter
capable of filtering contaminants from a fluid by means of
size-exclusion, mechanical interception, coagulation, or a combination
thereof, and said filter being adapted to significantly reduce fluid flow
and undergo blockage under a challenge by TOC contaminants, and filtering
the fluid through the microporous filter