Sewage sludge from municipal wastewater treatment plants in Germany is currently disposed via thermal treatment, agricultural utilization or is used for landscaping measures. With increasing focus on sanitation, soil protection and, most recently, on phosphorus recovery, the relevance of thermal sewage sludge treatment processes will be further enhanced. These processes allow environmentally friendly disposal with simultaneous phosphorus recovery.
The thermal sewage sludge treatment can be divided into various processes: The sewage sludge drying after dewatering further reduces the high water content of sewage sludge and is often preceded by following treatment processes. The processes for actual thermal disposal of sewage sludge can be divided into mono-incineration, co-incineration and alternative processes (e.g. pyrolysis and gasification). The majority of municipal sewage sludge in Germany is today incinerated, with approximately 50 % each in mono-incineration in stationary fluidized beds and in co-incineration in coal-fired power plants, cement plants and waste incineration plants. Due to the recently amended German Sewage Sludge Ordinance, the disposal path of co-incineration will be restricted in future. As a result, it is expected that the capacity for mono-incineration must be increased.
Sewage sludge – Drying – Mono-incineration – Co-incineration – Phosphorus recovery |