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Comparing MBR technology with the MBBR and CAS: how do the numbers stack up?

Using the Transcend modeling platform to benchmark conventional activated sludge with two alternative process technology options available for wastewater treatment

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San Luis Obispo WRRF

A report from the Water Resource Recovery Facility serving the City of San Luis Obispo in California

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MBR features

Search our in-depth feature articles on MBRs. Practitioners with experience of operating membrane bioreactor technology and academics researching this specialist area share their expertise.

Foaming in MBRsView all MBR features

About MBRs

A membrane bioreactor (MBR) is a wastewater treatment process where a perm-selective membrane is integrated with a biological process – a suspended growth bioreactor.

A membrane bioreactor is essentially a version of the conventional activated sludge (CAS) system. Whereas the CAS process uses a secondary clarifier or settlement tank for solid/liquid separation, an MBR uses a membrane. This provides a number of advantages relating to process control and product water quality.

About MBRsMBR acronym buster

Municipal & industrial treatment

There is no significant difference in the design of the MBR technology for a process treating industrial rather than municipal wastewater. The key differences between the two applications are that, for industrial effluents, there are:

  • higher concentrations of organic matter
  • more temporal variation in the concentrations of pollutants (seasonally and diurnally)
  • very significant variations across different industrial sectors, the most biorefactory effluents being from landfill leachate applications
  • no requirement for the removal of pathogenic micro-organisms, unless the effluent is combined with a sewage stream.

MBR case studiesMBR features

MBR costs

A full needs analysis is required before selecting a membrane bioreactor system, first of all to confirm that an MBR will be the most cost effective solution for a particular requirement, taking everything into account. Secondly, to ensure an MBR is the most appropriate choice of technology for the circumstances.

Feature − MBR OpexView all MBR features

Design and Operation

Operation and maintenance (O&M) parameters for an MBR include:

  • membrane side − flux, pressure, permeability, recovery, membrane aeration rate, and physical and chemical cleaning cycle times and protocols, and
  • biological side − hydraulic and solids retention time, and sludge recycle rate(s).

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Explore more content…

The MBR at Henriksdal: pilot and full-scale plant operation

Researchers at pilot-scale Hammarby Sjöstadsverk share their work in determining the operating conditions for Henriksdal WWTP in Stockholm, one of the largest MBRs in the world

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Membrane technology in controlling micropollutants and pathogens

Read our report on 'Discussing membrane technology: micropollutants and pathogens' attended by 30 people from across the world (April 2021)

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What are MBRs?

If you're new to MBRs, read our introduction to membrane bioreactors - and explore all our MBR Basics pages

What are MBRs?Advantages of MBRs

Immersed flat sheet MBR membranes: a summary of commercial products

In this first of three features exploring the MBR membrane market, Simon Judd summarises characteristics of some of the commercially-available immersed flat sheet membranes for wastewater treatment

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