Sewerage sludge incineration with integrated phosphorous recovery
With regards to the background of the planned sewerage sludge incinerator plant with integrated phosphorous recovery, the new Sewage Sludge Ordinance and the Fertilisation Ordinance specify that, from 2029, sewage sludge can no longer be distributed as fertiliser in fields to protect the ground and drinking water. The main reason is the encumbrance of the sewage sludge with pharmaceutical residue (among other antibiotics), heavy metals and synthetic materials (microplastics). One alternative option for utilising the sludge is a thermal application, i.e. incineration, which has already been practiced for several years. At the same time, the legislator stipulated that the recyclable material phosphorous has to be recovered from the sewage sludge and channelled back into the economic cycle. This also applies for the annual 30,000 tons (raw substance) of Kiel sewage sludge of the Bülk sewage treatment plant.
The necessity of future sludge disposal as well as experience from more than 40 years of waste incineration at the Theodor-Heuss-Ring site have led MVK to the decision to take on the planning of an additional incineration line for the conversion of 30,000 tons of sewage sludge into dry substance annually. Simultaneously, a partner was sought via an EU-wide invitation for tenders for the tasks which cannot be handled by MVK:
- Recovery of phosphorous from sewerage sludge ash
- Sewerage sludge acquisition
- Security of disposal in case of revisions and plant malfunctions of MVK
- Sewerage sludge transports
Negotiations is completed in 2021.
Environmental and climate protection
The central component of all planning is the best-possible protection and benefit for people and the environment. With the planned sewerage sludge incineration, MVK can provide carbon-neutral district heating for a further 4,000 Kiel households. Therefore, MVK is an inherent component of the city’s master plan for 100% climate protection status, and provides a significant contribution towards the climate-neutrality of the state capital Kiel. The mono-incineration of the sludge via an internal line offers the technical opportunity to recover the vital and finite raw material phosphorous contained in the ashes. This is just as important to MVK as being able to extensively integrate the new systems components into the existing structures. A further bonus for the environment is the processing of the water contained in the sewage sludge. In the future, it will be possible to replace 35,000 cubic metres of the fresh water required annually today for the operation of the waste incineration plant with water from the sewage sludge.
Funding through EU-Life
The environmental advantages of the sewerage sludge incinerator plant with integrated phosphorous recovery have also been convincing at a European level. The MVK project has become part of the EU Commission's "Green Deal" through funding from the EU "Life" project.