Drying of sewage sludge has to meet the conflicting demands between economic efficiency, energy supply, product requirements, disposal safety and utilization options. Drying of sewage sludge minimizes its mass, volume and disposal costs. The produced dry and disinfected biosolids are a valuable product that is well suited for its beneficial use. Different energy sources can be used to supply the heat required for drying. Huber uses a medium temperature design using temperatures up to 293 °F. This is because these temperatures are high enough to ensure quick drying and at the same time provide a cost-effective and eco-friendly utilization of waste heat. Internal recycling of dryer air via a condensator with integrated heat recovery reduces the heat demand of the dryer even more.