Smurfit Kappa Papier- und Pappenfabrik (paper and cardboard factory) in Diemelstadt-Wrexen is making absolutely positive experiences with two Delta Hybrid units. For several years they have supplied the aerobic aeration basin of the in-house wastewater treatment plant “under high pressure” with air or oxygen.
Every year the company needs about 800,000 cubic meters for production. After application in the in-house wastewater treatment plant the water is treated and discharged into a receiving water with a purity of 95 per cent.
The water is treated in accordance with the classic anaerobic/aerobic principle. First of all, it is cleaned 75 per cent from carbons by means of bacteria in an anaerobic reactor. As a result, in the second stage, the aeration basin, the efficiency of the bacteria decreases. Therefore, they have to be supported by feeding oxygen.
After having passed the following sedimentation basin, the waste water has the stipulated purity and can be fed into the adjacent receiving water.
In order to avoid a contamination of the receiving water, the return demands the use of absolutely oil-free compressed air in case of treatment in an aeration basin. Up to 2007 three oil-free compressing positive displacement blowers series GM 35 S (type Delta Blower) made by Aerzener did this job at Smurfit Kappa.
However, as usual in the industrial field also the aeration basin of Smurfit Kappa, for reasons of space, has a small floor space, but a remarkable height of 8 meters. To overcome this water column about 0,9 bar are necessary – which corresponds to a utilization of the positive displacement blowers of at least 95 per cent and after an operating period of ten years inevitably led to increasing maintenance costs.
In this situation Aerzener Maschinenfabrik offered remedial action by means of the at that time newly developed Delta Hybrid rotary lobe compressor for a maximum pressure of 1,5 bar. “Then, in 2007, we installed the first Delta Hybrid in our station. Although this unit was run immediately as base load unit in continuous operation, from the installation up to now there were no problems at all,” comments wastewater treatment plant manager Markus Jaschke. The experiences with this first Delta Hybrid unit were so positive that at the end of 2008 they decided to install a second Delta Hybrid unit.
»Since their commissioning both of the Delta Hybrid units are working absolutely failure-free. As per our experience of several years they are the ideal generators when absolutely oil-free compressed air up to a maximum pressure of 1,5 bar is required.«
