Co-incineration of dried sewage sludge in coal-fired power plants: a case study

With the ongoing investment in sewage treatment capacity in Flanders (Belgi um), a new challenge is the management of the rising amount of sludge. Sinc e sludge disposal to agriculture and landfill is regularly becoming Very di fficult, alternative thermal disposal routes become more important. This pa per presents the results of the various co-incineration tests with dried sl udge in coal-fired power plants. The aim of this project was to investigate whether adding dried sludge to the combustion process is technically possi ble, whether the emissions remain below the permitted levels, and whether t he quality of residual products remains acceptable. It is concluded that th e co-incineration of dried sludge is a valuable and responsible sludge disp osal option because it can be carried out in the existing units with a high electrical efficiency. Also, sludge disposal is achieved with a limited in fluence on emissions and residual ashes, without creating additional waste streams. The main points of attention are a limitation of the cc-incinerati on rate and the total input of sulphur, chloride and (earth) alkali element s to avoid corrosion and fouling problems.