Industrial wastewater is often characterized by highly varying flows and concentrations resulting in complex requirements for the wastewater treatment plant which often cannot be met by conventional technologies. In extended aeration systems those variations can lead to a deterioration of the sedimentation characteristics of the biomass, leading to loss of biomass and violation of the discharge consent.

This is one of the reasons MBR technology is increasingly used for industrial applications. Advantages of this technology include:

• As Membrane Filtration is an absolute barrier for the biomass, varying loads do not cause a loss of biomass.

• MBR plants have very low footprint requirements, as they are usually operating with an MLSS of 8-12 g/l, allowing a much more compact bioreactor. Secondary clarification is also obsolete. An existing conventional plant upgraded by an MBR system can process significantly higher loads and flows without the necessity to build additional tanks - a considerable advantage in crowded locations.

• All in all, the technology is most cost-efficient. Investments in a membrane filtration are defined by the hydraulic load, which is usually rather low in industrial applications. As membrane technology is exceptionally robust, the cost benefit analysis is very favourable.

A further significant advantage of membrane systems is the possible re-use as the effluent is hygienically safe and of high quality. A reduction of the water consumption is a major issue in industry, not only for monetary reasons. Environmental responsibility and public interest are also of importance. Therefore many industries aim to minimize their emission levels.