Thermal utilization of sludge

Legal framework conditions at European level, such as the IPPC Directive (2008/1/EC) and Waste Framework Directive (2008/98/EC), have led to a broad discussion on sustainable solutions for disposal of sewage sludge in the past few years.

Mono-incineration is one of the most promising methods for future utilization of sewage sludge. Sewage sludge differs substantially from other fuels, which is why there are special incineration processes available on the market. ANDRITZ can offer a process concept with a fluidized bed for large-scale plants, while the ANDRITZ EcoDry process, combining full drying with incineration in a cyclone furnace, is more suitable for decentralized plants. By including appropriate treatment stages, potential recyclables contained in the ash (particularly phosphate) can be recovered.

Depending on the requirements of the project concerned, the EcoDry process can be implemented with one of the three drying technologies available (drum drying, belt drying, fluidized bed drying).

Using a low-temperature belt dryer in combination with incineration of digested sludge in the cyclone furnace opens up new possibilities for energetic sewage sludge utilization with highest yields, placing the goal of energy self-sufficient sewage treatment plants within reach.