A fuel tank inerting prefilter assembly comprising: (a) a first endcap, wherein the first endcap includes a first side and a second side and a central opening passing from the first side through the second side; (b) a second endcap; (c) a first hollow cylindrical fluid treatment filter comprising a particulate removal and coalescer arrangement, the particulate removal and coalescer arrangement including a fibrous pleated porous medium having a pore size in the range from about 0.5 microns to about 50 microns; and an oleophobic and/or hydrophobic fibrous medium; (d) a second hollow cylindrical fluid treatment filter comprising an ozone depleting arrangement, the ozone depleting arrangement comprising an ozone depleting material; (e) a third hollow cylindrical fluid treatment filter comprising an organic vapor depleting arrangement, the organic vapor depleting arrangement comprising activated carbon, zeolites, and/or activated alumina; and, (f) a fourth hollow cylindrical fluid treatment filter comprising a particulate removal arrangement comprising a pleated porous medium, the filter having an ultra-low penetration air (ULPA) filter rating or a high efficiency particulate air (HEPA) filter rating; wherein the first hollow cylindrical fluid treatment filter, the second hollow cylindrical fluid treatment filter, the third hollow cylindrical fluid treatment filter, and the fourth hollow cylindrical fluid treatment filter are coaxially arranged, forming a filter unit having a top end and a bottom end; wherein the first endcap is bonded to the bottom end of the filter unit and the second endcap is bonded to the top end of the filter unit; the filter assembly defining a first fluid flow path and a second fluid flow path, wherein (i) the first hollow cylindrical fluid treatment filter is disposed across the first fluid flow path and the second fluid flow path, and (ii) the second hollow cylindrical fluid treatment filter, the third hollow cylindrical fluid treatment filter, and the fourth hollow cylindrical fluid treatment filter are disposed across the second fluid flow path; and wherein the first endcap comprises a fluid flow channel including a step-wise channel portion and an annular channel portion, and a coalesced fluid outlet, the fluid flow channel communicating with the coalesced fluid outlet, wherein the first fluid flow path includes the fluid flow channel and the coalesced fluid outlet. (a) a first endcap, wherein the first endcap includes a first side and a second side and a central opening passing from the first side through the second side; (b) a second endcap; (c) a first hollow cylindrical fluid treatment filter comprising a particulate removal and coalescer arrangement, the particulate removal and coalescer arrangement including a fibrous pleated porous medium having a pore size in the range from about 0.5 microns to about 50 microns; and an oleophobic and/or hydrophobic fibrous medium; (d) a second hollow cylindrical fluid treatment filter comprising an ozone depleting arrangement, the ozone depleting arrangement comprising an ozone depleting material; (e) a third hollow cylindrical fluid treatment filter comprising an organic vapor depleting arrangement, the organic vapor depleting arrangement comprising activated carbon, zeolites, and/or activated alumina; and, (f) a fourth hollow cylindrical fluid treatment filter comprising a particulate removal arrangement comprising a pleated porous medium, the filter having an ultra-low penetration air (ULPA) filter rating or a high efficiency particulate air (HEPA) filter rating; wherein the first hollow cylindrical fluid treatment filter, the second hollow cylindrical fluid treatment filter, the third hollow cylindrical fluid treatment filter, and the fourth hollow cylindrical fluid treatment filter are coaxially arranged, forming a filter unit having a top end and a bottom end; wherein the first endcap is bonded to the bottom end of the filter unit and the second endcap is bonded to the top end of the filter unit; the filter assembly defining a first fluid flow path and a second fluid flow path, wherein (i) the first hollow cylindrical fluid treatment filter is disposed across the first fluid flow path and the second fluid flow path, and (ii) the second hollow cylindrical fluid treatment filter, the third hollow cylindrical fluid treatment filter, and the fourth hollow cylindrical fluid treatment filter are disposed across the second fluid flow path; and wherein the first endcap comprises a fluid flow channel including a step-wise channel portion and an annular channel portion, and a coalesced fluid outlet, the fluid flow channel communicating with the coalesced fluid outlet, wherein the first fluid flow path includes the fluid flow channel and the coalesced fluid outlet.