Condition sewage sludge with this fluidized-bed mixer
Every year 220,000 metric tons of sewage sludge are generated by the Bottrop sewage-treatment plant and neighboring plants. In order to guarantee an optimum thermal process, this sewage sludge must be conditioned prior to incineration. The focus is thereby placed on dry matter (DM) content — a specific mixing ratio of moist and dried sewage sludge and a high degree of homogeneity are essential for the quality of thermal utilization. Trials have shown that mixing and texturing in this company’s KM DW Ploughshare mixer (photo) is a suitable process for the conditioning of sewage sludge. Specially developed shovels rotate close to the wall inside a horizontal drum, generating a fluidized bed. The process enables a high level of homogeneity and consistent reproducibility. At the Bottrop plant, two KM 600 DW Ploughshare mixers have been installed. An automated transport process is used to continuously feed the mixers with moist and partly dried sewage sludge. Also, the drying was developed with an emphasis on sustainability: the solar thermal drying system, specially built for pre-treatment, is one of the first of its kind in Europe. Hall A2, Stand 129— Gebrüder Lödige Maschinenbau GmbH, Paderborn, Germany