The wastewater from the Leverkusen Chempark, and its nearby households, is biologically biodegradable – but requires a constant supply of compressed air. This process is operated by Currenta and, since 2007, the aeration of the open basin has been carried out using centrifugal air blowers from Atlas Copco, which replaced the classic surface aerators.
Norbert Meier-Külschbach, who is responsible for the operation of the plant explained:
“Bacteria can only maintain their activity for a few hours without oxygen. So a continuous supply is crucial.”
Consequently, Currenta signed a maintenance agreement for five years with Atlas Copco and installed the remote maintenance system Air-Connect. Any malfunctions in the installation are reported to the central office at Atlas Copco immediately. They can access the control system externally or send a technician to the installation if needed.
Efficiency gains of 40% – and greater durability
Four ZB machines were installed, of which two or three operate around the clock, depending on the degree of contamination of the waste water, and the fourth one serves as a contingency reserve. “We are running 365 days a year in 24-hour operation,”
The turbo blowers are oil-free single-stage, speed-controlled type
ZB 160 VSD machines, which are controlled for energy optimization using
the ES 130T higher level control unit. This separate control unit can also
be retrofitted for existing installations. The motors have a contactless
electromagnetic bearing system, which minimizes maintenance.
The impeller is also mounted on the motor shaft itself; this omits the gear completely, allowing for outstanding efficiency, and does not require any extra lubricant, so that oil cannot get into the blower. Compared with conventional rotary lobe blowers, this new type of drive achieves a possible energy saving of 30-40%, which may even be significantly higher in individual cases.
According to a statement from Meier-Külschbach, Currenta also needs turbine
technology because normal rotary lobe blowers can only provide 1 bar of
overpressure. In the waste water treatment plant, the water depth and
the special membrane pipe system on the bottom of the basin require a
significantly higher pressure.
“The compact design of the machines was also important to us, especially considering the construction situation in Uerdingen where we wanted to use new compressors and we wanted one supplier to provide the equipment for both locations.”