Process for the thermal sewage sludge treatment
A termination of the sewage sludge application on agricultural areas was fixed in the coalition agreement of the 18th legislative period of the German Federal Parliament. In 2016, the "Ordinance on Reorganisation of Sewage Sludge Utilisation" for notification in Brussels, was submitted. After expiration of the standstill period on 27th December 2016, the draft goes to the parliamentary procedure/Federal Council, so that in case of an enactment, amongst others the following amendments occur:
- A recovery of phosphorus will be established compulsory.
- Deadlines for a recovery of phosphorus become defined, so that for a sewage plant with more than 100,000 population equivalents 12 years after commencement of the enactment, the recovery of phosphorus becomes compulsive.
- The scope will be extended for non-agricultural areas.
- A quality assurance will be regulated.
- Ground-related limits (according to BBodSchV, Federal Soil Protection Ordinance) and material-related limits will be defined by the DüMV (Fertiliser Ordinance).
In the future, an agricultural utilisation of sewage sludge as fertiliser and a related nutrient recovery is severely restricted or rather excluded, so yearly about 620,000 t of dry matter sewage sludge, which are used for agriculture and cultivation in 2015, has to be added to successive alternative methods of utilisation .
Currently alternatives of agricultural sewage sludge application are only available in thermal sewage sludge treatment processes: in addition to classical combustion (mono-combustion and co-combustion), these are pyrolysis, gasification or hydrothermal carbonization (HTC). Depending on the respective technical level of development and procedural implementation, these procedures offer different possibilities for the political strive for recovery of phosphorus and save a long-term disposal of sewage sludge.
As the leading professional association, the German association for water, wastewater and waste e.V. (DWA) deals with the disposal of sewage sludge and offers detailed regulations, current information and meetings among others about this topic. Against this background, Dr. Rebling will present an overview about the thermal processes for sewage sludge treatment on 19th January 2017 on the 3. Networking Day of the Sewage Sludge Network North-East of the DWA.
 EUWID Recycling und Entsorgung 51/52.2016