Treatment of Waste Water
from Membrane Filtration

In the membrane bioreactor (MBR), hollow fiber membranes purify the water from the biological waste water treatment plant, either in the activation tank or secondary sedimentation basin. The membrane-filtered purified water is discharged and a fine surplus activated sludge remains which cannot be compared with the coarse sludge obtained with alternative technologies.

GEA Westfalia Separator has designed the MBR decanter specifically for maximum dewatering of the very homogenous fine sludge at high throughput capacities. A special rotor geometry, with a specific inlet and discharge diameter, has been developed for the scroll and bowl of the decanter for this purpose. As a result of this modification, the dewatering efficiency of the MBR decanter is up to five percent higher than standard decanters available on the market or up to ten percent higher than can be achieved with alternative technologies such as strainer belt presses. This means approximately 20 to 30 percent less residual volume and thus considerably lower disposal costs for the operator of the MBR machines.

A further advantage is the continuous operating mode: whereas presses regularly have to be flushed and cleaned, there are no process interruptions with the GEA Westfalia Separator MBR decanter. The new geometry also reduces the consumption of flocculents and requires less electricity. In addition, this decanter is also a closed system. It is not possible for any aerosols to escape and pose a hazard to the operating personnel or the environment. Last but not least, the MBR decanter impresses with its small size. The space requirement is so low that no investments are required for new buildings.