Thermal Treatment of Sewage Sludge – State of the Art and Evaluation of the Variants –
The future disposal of sewage sludge in agriculture or on landfills will no longer prevail due to environmental impacts which will enforce legal restrictions. Therefore, sustainable and environmentally friendly alternatives are required. The thermal treatment of sewage sludge has been established successfully in Central Europe and offers such an alternative.
In an evaluation of different process variants which are offered today, it has been shown, that the most preferred system for large scale mono-combustion of sewage sludge is the incineration in stationary fluidized bed system. An effective means of sludge pre-treatmentand energy recovery from the drying process can increases the energy benefits of the procedure significantly.
Due to pending legal changes (landfill ban) and foreseeable limitations on agricultural use, the disposal of sewage sludge in the future will increasingly be done by thermal treatment.
With around 17 MJ kg/TR (raw sludge around. 70 % GM) sewage sludge has a high energy potential, which can be used to satisfy the energy demand (electrical and thermal) of a wastewater treatment plant with sludge digestion and incineration and provide surplus energy available to the grid. Wastewater treatment plants without sludge digestion and incineration have to completely cover their need by external energy.
The European Commission recommends the fluidized bed technology due to high combustion efficiencies and low exhaust gas volumes as state of the art. In addition, pre-treatment of the sludge by drying is recommended in order to avoid the use of supplementary fuels.
The present paper deals with sewage sludge as fuel and its thermal utilization. Different thermal process technologies as well as the associated flue gas cleaning processes are considered to describe the current status of the thermal treatment of sewage sludge.
| Copyright: | © TK Verlag - Fachverlag für Kreislaufwirtschaft | |
| Quelle: | Waste Management, Volume 3 (Oktober 2012) | |
| Seiten: | 13 | |
| Preis inkl. MwSt.: | € 0,00 | |
| Autor: | Jörn Franck  Dipl.-Ing. Josef Lux Dr.-Ing. Guomin Zhang Ralf Wittstock | |
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