Fluid flow distribution device

In a first membrane filtration module comprises a membrane module comprising a plurality of permeable hollow membranes; a fluid distribution device adapted to removably surround at least a portion of the membranes of the membrane module, the fluid distribution device comprising a plurality of through-hole openings for distributing a fluid, and the fluid distribution device adapted to distribute a flow of fluid along a surface of the permeable hollow membranes. In a second membrane filtration device comprises a membrane module comprising a plurality of permeable hollow membranes, each of the permeable hollow membranes having a surface; and a gas distribution device: adapted to distribute gas bubbles to the surface of the permeable hollow membrane, adapted to removably surround at least a portion of the plurality of permeable hollow membranes, and defining a plurality of through openings for distributing the gas bubbles to the membranes.