Your web browser is out of date.

Update your browser for better security, speed and to get the best experience on this website.

Update your browser

MBR membrane technology terms

Posted on
An image to illustrate an array of terms relating to membrane technology - cassette, tube, module, skid, frame, sheet, candle, stack, cartridge, loop, panel, element and sub-unit.

Membrane elements, modules, stacks and trains

Terms for the individual components of a membrane technology are used inconsistently for membrane bioreactors.

  • An ‘element’ can be considered to be the smallest replaceable component of the membrane technology.
  • The term ‘module’ normally applies to a single element for a rectangular hollow fibre technology, but usually to a collection of elements in the case of flat sheets.
  • The term ‘stack’ can be considered to apply generally to a collection of elements, though the terms ‘rack’, ‘unit’, ‘cassette’ and ‘skid’ are also used.
  • A collection of immersed stacks is usually called a ‘train’, and the train may include the biological tank.
Table 1. Terminology for MBR membrane products and technologies
Component Flat sheet (FS) Hollow Fibre (HF) rectangular panel Hollow Fibre (HF) cylindrical bundle; Multitube (MT)
ElementPanel, element, sheet, cartridgeModule, sub-unitModule
Collection of elements IModule, cassette, unitRack, cassette, cartridge, moduleSkid
Collection of elements IIStack, frameStack, frame

A number of abbreviations are used for the different polymeric membrane materials, as well as for the MBR process configurations. The process configuration defines how the membrane is integrated into the overall MBR process. It can be either immersed (or 'submerged') in a tank (hence the term iMBR) or placed outside of the tank as a sidestream (i.e. an sMBR).


All comments are moderated and may be edited or deleted at any time. You must not post anything that is defamatory, illegal, offensive or which contravenes our privacy policy guidelines. Email addresses are only used for comments purposes. Contact to remove or edit a comment.

About this page

'MBR membrane technology terms' was written by Simon Judd

This page was last updated on 19 August 2021


Information on this page may have been supplied by third parties. You are reminded to contact any third parties to confirm information is accurate, up to date and complete before acting upon it. accepts no liability for information provided by third parties, actions taken on the basis of this information or information held on third-party websites.

© Text copyright Judd & Judd Ltd unless otherwise indicated on this page