Latest Situation
Incineration is used to dispose of sewage sludge, although the PE or lime-conditioned press cakes are not actually suitable for an incineration process. Sewage sludge press cake has a water content of more than 60%.
Current Problem
Therefore, incineration only works after prior drying or with an appropriate supporting fire. In any case, however, the energy consumption is so high that it is completely unrealistic to want to use sewage sludge incineration for a significant net energy gain for electricity generation.
AGT-Solution
The situation is completely different for sewage sludge conversion. Of course, 60% water content cannot be easily utilised here either, but in a reform stage downstream of the actual conversion process, the sludge’s own waste heat can be used for sludge drying.
The dried organic fraction contained in the sludge is then converted into high-grade gas and converted into electricity using a turbine-generator station.
To maximise the net energy gain, it is crucial whether the converted sewage sludge is digested sludge or not.
Benefit
- The residual organic content in the ash is less than 5%, which means that it is suitable for landfill throughout the EU.
- A significantly more cost-effective plant operation results from the continuously more favourable operating costs due to lower personnel requirements, sludge drying through waste heat, no additional supporting fire.
- The LTC process enables a considerably higher degree of efficiency in electricity generation through the operation of gas and steam turbine combinations.