TORNADO® Pumps make good Economic Sense

Membrane Technology is a rapidly-growing application in wastewater treatment. It is a combination of membrane ultra-filtration with traditional biological treatment of municipal or industrial wastewater. The ultra-filtration is used to separate the effluent (clear water) from active sludge. For more than 10 years TORNADO^® rotary lobe pumps are used reliably in this technology. Technical advantage of the pumps are that it is easy to control, has a high suction capability and a low NPSHr. Last but not least the Pump has a compact design and saves a lot of space for the entire MBR plant.

The biggest advantages for the end user and operator are that such an MBR plant requires less space compared to a traditional wastewater treatment plant, the effluent (or filtrate) is filtered down to an average of 0.1μ, and the filtered water (effluent) is 100% bacteria free.

See the TORNADO^® Rotary Lobe Pump in use.

This application is traditionally handled with centrifugal pumps. But since the filters (membranes) have to be cleaned between filtering cycles, another pump has to prime the water through the filter. This process is called backwash. This is precisely the point where rotary lobe pump technology becomes very interesting.

The Rotary Lobe Pump can be operated bi-directionally, for example, pumping can be in both flow directions. First 'filtration' takes place and second 'filter (membrane) backwash. Other technical advantages of the Rotary Lobe Pump are that it is easy to control, since it is a positive displacement pump with a high suction capability and a low NPSHr. Last but not least the Rotary Lobe Pump, especially our TORNADO^®, has a compact design and saves a lot of space for the entire MBR plant.

Pumps are used reliably for more than 10 years
NETZSCH sold its first TORNADO^® pumps for the MBR application almost 10 years ago in 2006. These pumps are still running perfectly and both the operator and the plant builder (large international contractor) are very satisfied.

Our most recent success has been in southern Europe. One interesting example is in Milan, Italy. The municipal water treatment plant in Rozzano uses an MBR technology plant. The plant requires a pumping system capable of permeate extraction and membrane cleaning simply by changing the pump‘s rotation and the flow direction. The membrane process is handled with six XLB-6/2 pumps (see photo). In order to save even more space, the 37kW motors are mounted on top and drive the pumps via a belt. In the filter process, the capacity is around 195 mc/h per pump. After a certain filtering time the membranes get dirty and cleaning is required. Now the above-mentioned backwash process starts. The pumps prime the water back through the filters (membranes with an average capacity of 300 mc/h per pump). These second-biggest TORNADO^® pumps have now been in operation for around three years with great success. In the meantime, NPS has supplied the TORNADO^® T1 and T2 for many MBR plants and we will have great opportunities in the future in this important field of environmental management.