The project: Establishing the cause of pump failure
Four Sewatec D pumps installed in the return sludge pumping station of the Altenstadt waste water treatment plant had been experiencing failures at regular intervals. After commissioning, KSB Guard found that the vibration limit specified had been exceeded frequently. The maximum value measured for all four pumps was over 18 mm/s – well above the limit of 5 mm/s.
The customer: Abwasserverband Altenstadt
The municipality of Altenstadt is located in the Wetteraukreis region of Hessen, Germany, and comprises eight districts. The waste water treatment plant of Abwasserverband Altenstadt (Altenstadt waste water association) ensures urban drainage and trouble-free waste water disposal for the municipality’s 12,000 inhabitants. The waste water treatment plant has been designed for up to 25,000 inhabitants.
The challenge: Determining external factors
Biological treatment is an important step in the waste water treatment process which involves dissolved organic substances and nitrogen compounds being decomposed by microorganisms. The activated sludge from the final clarifier is then returned to the aeration tank. Following the recurrent failures, KSB Guard was installed and commissioned to enable data on the condition of the return sludge pumping station to be viewed at any time.
The solution: Failure diagnosis via long-term measurement
Thanks to KSB Guard it was possible to find the cause for the recurring vibrations: the discharge pipe had been directly mounted to the pumps instead of being suspended from the ceiling. As a result, the pumps had to bear the discharge pipe’s load which meant that remedial action was required. Two months after putting KSB Guard into operation, the piping installation was modified. Modification work involved attaching a load-bearing steel structure to the ceiling and fitting flexible rubber inserts between the piping and the pumps.
After returning the pumps to service, the vibration values dropped below 1 mm/s after only a short time – a result the customer was more than satisfied with. Until this point the Altenstadt waste water association had been testing KSB Guard free of charge, but now came the decision to purchase KSB Guard and install it permanently in the plant as a monitoring solution.
KSB Guard’s straightforward installation proved to be a particularly convincing feature. In addition, all registered users have round-the-clock access to the pumps’ data via the KSB Guard web portal and are immediately notified by e-mail in the event of any irregularities, allowing major damage and breakdowns to be reliably avoided.
Figures I Data I Facts
Plant: The return sludge pumping station of the Altenstadt waste water treatment plant
End user: Abwasserverband Altenstadt
Starting point: Regular failures of 4 Sewatec D pumps
Vibration values measured prior to remedial measures: above 18 mm/s
Vibration values measured after remedial measures: below 1 mm/s
Cause: Incorrectly supported piping above the pumps
Tool used for pump monitoring: KSB Guard