Aufarbeitung von Kühlschmierstoffen im Festbett-Umlaufreaktor
Treatment of coolants in fixed bed recycle reactors
In metal working, liquid and solid wastes occur from coolants, cleaning solutions, and shavings. They form a mixture of aqueous, oily, and particulates. DaimlerChrysler AG has submitted these residues and wastewaters from the splintering metalworking to various separation steps. These mixtures are collected and after a prefiltration are treated to emulsion cleavage in an ultrafiltration facility. The filtrate contains dissolved metals, the concentration of which can exceed the lawful stipulated introductory value. For this reason, the Fraunhofer-Institut fuer Grenzflaechen- und Bioverfahrenstechnik since 1996 has been commissioned by DaimlerChrysler to develop a biotechnical process to reduce the concentration of the dissolved metal ions through biological processes of the precipitates. Sulfate-reducing microorganisms are used. At first, a suitable microflora of sulfate-reducing bacteria was cultivated. These microorganisms were immobilized on porous materials for use i n a fixed bed recycle reactor. The tests are described.