• Back to Good Practices

How the membrane bioreactor works

The membrane bioreactor (MBR) combines biological treatment with membrane separation. The treated water is separated from the purifying bacteria (active sludge) by a process of membrane filtration rather than in a settling tank as in conventional systems. Only the treated effluent passes through the membrane. It is then pumped out. The sludge is recovered and dewatered.

Improved performance

The biomass contained in an MBR is far more concentrated, varied and lasting than in a conventional system. These properties enhance treatment efficiency. Since the MBR was installed, the Palencia plant has cut the chemical oxygen demand (COD) index at the biological plant outlet by 30%.

In January 2002, the Palencia plant replaced its biological treatment plant using the activated sludge process with the membrane bioreactor process. The Douai and Sovab sites have also introduced the technology.

• Back to Good Practices