Energy from Waste

Safe disposal of sewage sludge

Sewage sludge contains a high proportion of phosphorous and is frequently used as a fertiliser. Many countries aim to prohibit this in future, due to the high level of heavy metal pollution. In general, three methods of disposal remain: 

  • Landfilling, which leads to enormous sludge lakes, combined with the familiar problems of dumping contaminated waste. Landfilling is prohibited in some countries.
  • Disposal by means of anaerobic fermentation, which allows energy recovery by means of  methane gas extraction.
  • Mono-incineration and co-combustion. In principle it is possible to recover phosphorous through incineration, and also to recover energy by means of thermal recovery. In the case of mono-incineration, the sewage sludge must first be treated (dried and pelleted). Direct co-combustion is possible.

From a purely energetic perspective, the incineration of sewage sludge is an interesting alternative and at the same time a logical solution. Prior treatment by drying increases the calorific value of the sewage sludge, which can then be used as a standard substitute fuel in waste-to-energy plants. The calorific value of dried raw sludge is similar to that of dried brown coal (up to 19 MJ/kg).

 One possibility to dispose of untreated sewage sludge is by incineration in a rotary kiln. Here, paste-like waste can be fed into the furnace by lance. Disposal by gasification, using a DMS Direct Melting System, is also possible. 

Prior to drafting a concept for sewage sludge disposal, defining the objective is key. Is it more important to just dispose off the sewage sludge, without any great effort? What other disposal challenges need to be overcome? We will deliver the most suitable concept – and the right plant.  

Co-combustion in the thermal waste recovery process ensures the safe disposal of sewage sludge

Co-combustion in the thermal waste recovery process ensures the safe disposal of sewage sludge

Steinmüller Babcock Environment GmbH

Fabrikstraße 1

D-51643 Gummersbach, Germany

+49 (0) 2261 85 - 0

+49 (0) 2261 85 - 2999