Membrane module for separating a fluid feed stream which comprises permeate material and retentate material into a permeate stream and a retentate stream, comprising: a. a substantially box-shaped 20', 40', 45' HC, 45' PW or 53' HC container, with an internal space, the internal space is defined by a floor, two to four side walls and a roof, wherein the internal space has a width, height and length; b. one or more fluid inlet openings in at least one side wall; c. one or more retentate outlet openings in at least one other side wall, which are in flow connection with the fluid inlet openings, for discharging the retentate stream; d. one or more permeate outlet openings in at least one floor, side wall or roof (60, 70, 80) for discharging the permeate stream; e. one or more membrane pocket stacks arranged inside the container, which comprise membrane pockets arranged in the form of a stack and, adjacent to the one or more fluid inlet openings and/or the one or more retentate outlet openings, first spacers between the membrane pockets, which keep the membrane pockets spaced apart, in order to make a free flow cross-section for the throughflow of the fluid feed stream and/or the retentate stream possible, wherein the membrane pockets each comprise two membranes each on one carrier material and one or more second spacers between the membranes, which keep the membranes spaced apart from each other, in order to make a free flow cross-section for the throughflow of the permeate stream through the membrane pockets possible, and wherein the membranes of a membrane pocket are connected to each other at the edges, in order to prevent the fluid feed stream and/or the retentate stream from penetrating into the membrane pockets; f. one or more permeate tubes, which lead, perpendicularly to the flow direction of the fluid feed stream, to the one or more permeate outlet openings, wherein the one or more permeate tubes comprise one or more radial openings, through which the permeate material from the membrane pockets arrives in the one or more permeate tubes, and wherein first seals are fitted on the one or more permeate tubes between the membrane pockets, which first seals prevent the fluid feed stream and/or the retentate stream from coming into contact with the one or more permeate tubes, and wherein the one or more membrane pocket stacks extend substantially along the entire length, width and height of the internal space of the container, except for the area or areas in which the permeate tube or tubes extend. a. a substantially box-shaped 20', 40', 45' HC, 45' PW or 53' HC container, with an internal space, the internal space is defined by a floor, two to four side walls and a roof, wherein the internal space has a width, height and length; b. one or more fluid inlet openings in at least one side wall; c. one or more retentate outlet openings in at least one other side wall, which are in flow connection with the fluid inlet openings, for discharging the retentate stream; d. one or more permeate outlet openings in at least one floor, side wall or roof (60, 70, 80) for discharging the permeate stream; e. one or more membrane pocket stacks arranged inside the container, which comprise membrane pockets arranged in the form of a stack and, adjacent to the one or more fluid inlet openings and/or the one or more retentate outlet openings, first spacers between the membrane pockets, which keep the membrane pockets spaced apart, in order to make a free flow cross-section for the throughflow of the fluid feed stream and/or the retentate stream possible, wherein the membrane pockets each comprise two membranes each on one carrier material and one or more second spacers between the membranes, which keep the membranes spaced apart from each other, in order to make a free flow cross-section for the throughflow of the permeate stream through the membrane pockets possible, and wherein the membranes of a membrane pocket are connected to each other at the edges, in order to prevent the fluid feed stream and/or the retentate stream from penetrating into the membrane pockets; f. one or more permeate tubes, which lead, perpendicularly to the flow direction of the fluid feed stream, to the one or more permeate outlet openings, wherein the one or more permeate tubes comprise one or more radial openings, through which the permeate material from the membrane pockets arrives in the one or more permeate tubes, and wherein first seals are fitted on the one or more permeate tubes between the membrane pockets, which first seals prevent the fluid feed stream and/or the retentate stream from coming into contact with the one or more permeate tubes, and wherein the one or more membrane pocket stacks extend substantially along the entire length, width and height of the internal space of the container, except for the area or areas in which the permeate tube or tubes extend.