A filtration apparatus which comprises: a tubular casing which includes a longitudinal axis and first and second casing ends; a plurality of partition plates which are positioned in the casing and are sealed thereto to thereby define an intake collection chamber between a first of said partition plates and the first casing end, a discharge collection chamber between a second of said partition plates and the second casing end, and a reject collection chamber opposite the second partition plate from the second casing end; a plurality of elongated filtration membrane stacks which are positioned side-by-side in the casing generally parallel to the longitudinal axis, each filtration membrane stack comprising an intake end which is fluidly connected to the intake collection chamber, a discharge end which is fluidly connected to the reject collection chamber, and a permeate channel which extends between the first and second ends and is fluidly connected to the discharge collection chamber; an intake pipe which is connected to the intake collection chamber; a discharge pipe which is connected to the discharge collection chamber; and a reject pipe which is connected to the reject collection chamber; wherein a fluid to be filtered is communicated to the intake collection chamber through the intake pipe and is separated by the filtration membrane stacks into a permeate which is discharged from the discharge collection chamber through the discharge pipe and a reject fluid which is discharged from the reject collection chamber through the reject pipe; wherein each filtration membrane stack is comprised of a plurality of filtration membranes, wherein each filtration membrane is sealed in a corresponding hole in a corresponding partition plate, wherein each filtration membrane comprises an inlet end, an outlet end, and a permeate passage which extends axially between the inlet end and the outlet end, and wherein the outlet end of each filtration membrane is axially spaced apart from a next partition plate located closer to the second casing end such that the outlet of each filtration membrane is positioned in a chamber formed between its corresponding partition plate and the next partition plate; wherein, in each filtration membrane stack, the permeate passages of the filtration membranes are connected together to define the permeate channel and an end of the permeate channel located adjacent the intake end is sealed from the intake collection chamber. a tubular casing which includes a longitudinal axis and first and second casing ends; a plurality of partition plates which are positioned in the casing and are sealed thereto to thereby define an intake collection chamber between a first of said partition plates and the first casing end, a discharge collection chamber between a second of said partition plates and the second casing end, and a reject collection chamber opposite the second partition plate from the second casing end; a plurality of elongated filtration membrane stacks which are positioned side-by-side in the casing generally parallel to the longitudinal axis, each filtration membrane stack comprising an intake end which is fluidly connected to the intake collection chamber, a discharge end which is fluidly connected to the reject collection chamber, and a permeate channel which extends between the first and second ends and is fluidly connected to the discharge collection chamber; an intake pipe which is connected to the intake collection chamber; a discharge pipe which is connected to the discharge collection chamber; and a reject pipe which is connected to the reject collection chamber; wherein a fluid to be filtered is communicated to the intake collection chamber through the intake pipe and is separated by the filtration membrane stacks into a permeate which is discharged from the discharge collection chamber through the discharge pipe and a reject fluid which is discharged from the reject collection chamber through the reject pipe; wherein each filtration membrane stack is comprised of a plurality of filtration membranes, wherein each filtration membrane is sealed in a corresponding hole in a corresponding partition plate, wherein each filtration membrane comprises an inlet end, an outlet end, and a permeate passage which extends axially between the inlet end and the outlet end, and wherein the outlet end of each filtration membrane is axially spaced apart from a next partition plate located closer to the second casing end such that the outlet of each filtration membrane is positioned in a chamber formed between its corresponding partition plate and the next partition plate; wherein, in each filtration membrane stack, the permeate passages of the filtration membranes are connected together to define the permeate channel and an end of the permeate channel located adjacent the intake end is sealed from the intake collection chamber.