Waterleau has left the limited end-of-pipe thinking approach and has switched to a process-integrated approach.
The Membrane BioReactor (MBR) ideally fits in this philosophy. It produces an effluent that is extremely pure and appropriate for immediate reuse: no wonder that it is considered worldwide as the most promising techno logy for wastewater treatment. Micro- and ultrafiltration membranes can be used for the separation of sludge and biologically purified wastewater.
By replacing the sedimentation step by a membrane separation it is possible to operate the bioreactor at much higher sludge concentrations (typically 12 to 15 g/l). Hence, the volume of the bioreactor can be reduced drastically (by a factor of 3). An additional advantage of this system is the fact that the filtrate is virtually free of suspended solids and bacteria since these cannot pass the membranes. The filtrate will thus be ready for reuse or for further treatment by reverse osmosis.
There are two types of MBR's:
1. membranes placed externally, i.e. in an external loop to the bioreactor (X-TRACTOR® MBR)
2. submerged in the activated sludge, i.e. in the bioreactor itself (ATLANTIS® MBR)
Both membrane bioreactor concepts have there own advantages and they have their own range of application.
In an ATLANTIS® membrane-bioreactor reinforced hollow fiber membranes are being submerged in the bioreactor.
In case of a submerged membrane-bioreactor the membranes are submerged in the activated sludge, either directly or in a separate extraction compartment. In a submerged MBR, the membranes are kept clean by means of an efficient coarse bubble aeration which ensures a good sludge management in the membrane module and guarantees turbulent conditions at the membrane surface. A submerged MBR is hence characterized by a very low energy consumption and is able to treat wastewater in a very compact installation. The ATLANTIS® submerged MBR solution is generally used for treating larger flows or wastewater not requiring harsh and frequent cleanings of the membranes.
The WATERLEAU ATLANTIS® submerged MBR is equipped with durable reinforced hollow fiber membranes allowing easy cleaning and efficient backpulse on one hand and ensuring long membrane lifetime on the other.