The company processes and refines liquid cooking oils for the food industry. At the first stage the waste water is approx. 60 °C, acidic (ph-value 1,5 up to 2,0) and contains cooking fat. These fat components, so-called COS-materials (chemically oxygen sorbent materials) have to be removed before the discharge of the waste water into an adjacent area. To achieve this it is treated in a sewage plant using both chemical and biological technology.
In the first phase the ph-value is neutralized and fat components congeal by the introduction of lime. In the second phase bacteria take over the further reduction of the COS-value in two clarifiers by “eating” the remaining fat components. Oxygen blown into both clarifiers reinforces the work of the bacteria and its increase. In the third stage the remaining ingredients are pushed to the surface and skimmed off, the cleansed water is then pumped into the lakes in the proximity.
The new Delta Hybrid produces compressedair for the second treatment stage replacing three positive displacement blowers of Aerzener Maschinenfabrik manufacture which have been in operation since commissioning of the sewage plant in year 1992. The upgrade was necessary as these three units with motors of 15 kW each and a pressure of 1,0 bar, the maximum possible for positive displacement blowers, could not reach the required oxygen content in both clarifiers.
Now the Delta Hybrid with a motor power of 37 kW and the possibility of generating 1.5 bar can supply both clarifiers with compressed air. With an average load of approx. 60 percent the Delta Hybrid is running with a maximum pressure of only 1,3 bar – a saving of approx. 40 percent of energy is the end result.
The Delta Hybrid has run without any problems since its commissioning and to the complete satisfaction of the operator. The optimum concept for the future is the installation of a second unit to run alongside an existing unit and to run both on an alternate basis. Either way Aerzener Maschinenfabrik has promised the availability of service within 24 hours. The long-standing support, design of all projects and service by Aerzener Maschinenfabrik give the operator confidence in both the product and manufacturer.
