PRIMARY SLUDGE TRANSFER, SERBIA

primary sludge transfer pumpsThis new plant consists of two technical units, a water line and sludge line with gas utilization.  Total investment value, exceeding 17 million EUR, is financed by EBRD, EAR and Municipality of Subotica.  The main aim of the project was to raise the quality of the water and waste treatment, as well as protecting the environment and the local lake Palic.

In September 2009, Dutch company DHV B.V., who were awarded the contract for this project, contacted AxFlow kft, Mono's distributor in Hungary, to quote for some pumps and replace the existing vertical sludge pumps. 

Due to the dry solids content within the primary sludge and the changes in sludge viscosity in the settling tanks, the existing pumps could not cope.

AxFlow therefore specified four Compact C Range progressing cavity pumps to transfer the sludge at a capacity of 25m3/h and 2.5 bar discharge pressure.  All the pumps have a 5.5kW drive motor, IP65 protection and PTC elements so they can be regulated by frequency inverters.

To protect the pumps from accidental dry running, the pumps were also specified with temperature probes that will measure the temperature of the stator.  If fluid does not reach the pump, the stator will start to heat up.  If the temperature becomes 10% higher than the normal working conditions, the pump will automatically stop to avoid damage.

Due to the dry, abrasive solids present in the fluid, the pumps have been supplied with alloy steel 0.25mm hard chrome plated rotors.

Pump rotational speed is less than 250 rpm so will ensure a longer lifetime for the stator and lower maintenance costs.

For more information, please e-mail djordje.bebic@axflow.hu or visit www.axflow.com/hu/