Sewage sludge recycling

Doing what matters, together.
Treating sewage sludge safely and laying the foundation for phosphorus recycling.

Municipalities need to decide today how they will safely treat their sewage sludge in the future and meet the requirements for phosphorus recovery. EEW supports them with long-term sewage sludge mono-incineration solutions.

Unlike co-incineration with other waste, mono-incineration treats sewage sludge separately. Organic pollutants are largely destroyed and pathogens eliminated. At the same time, the phosphorus contained in the sewage sludge remains concentrated in the resulting ash. This creates a suitable feedstock from which phosphorus can be recovered in downstream processes.

EEW already operates sewage sludge mono-incineration plants at several locations. Existing infrastructure and integration into our plant network and waste stream management help us manage sewage sludge volumes reliably – including during scheduled maintenance or operational disruptions. Together with specialised partners, we are also developing pathways to enable the phosphorus contained in sewage sludge ash to be recovered and put to further use in the future.

We turn waste into energy and challenges into solutions.

The thermal treatment of sewage sludge is becoming increasingly important. For decades, it was common practice to use certain sewage sludges as fertiliser in agriculture. The legislator has now introduced new requirements for sewage sludge recovery, particularly with regard to phosphorus recovery.

As one of Germany’s major companies in the generation of electricity and heat through thermal waste recovery, we are taking on this important task and aim to contribute to the further development of sewage sludge recovery. For municipalities, we develop site-specific solutions that are geared towards future statutory and technical requirements. Benefit from our experience in reliable sewage sludge recovery for your region.

Sewage sludge. A challenge for soils and water bodies.

Sewage sludge is generated during wastewater treatment. It contains substances that modern wastewater treatment plants filter out of wastewater in a complex process in order to protect rivers, seas, groundwater and, not least, our drinking water reservoirs.

Every year, around 1.8 million tonnes of sewage sludge dry matter are generated in Germany from the treatment of municipal wastewater. In particular, sewage sludges from wastewater treatment plants in large cities and urban areas can be contaminated with pollutants such as heavy metals, organic pollutants, residues of pharmaceuticals, pathogens and microplastics. At the same time, sewage sludge also contains phosphorus as a resource. This nutrient, which is important for plants, promotes growth. This is one reason why sewage sludge was used as fertiliser in agriculture for decades.

Over time, the agricultural use of sewage sludge has increasingly been viewed critically. Despite pretreatment, sewage sludge may contain substances that can enter soils and water bodies and may therefore also have an impact on the environment.

In addition, an oversupply of phosphates can promote eutrophication, or over-fertilisation, of streams, rivers and lakes. This is why safe, compliant and resource-oriented sewage sludge recovery is becoming increasingly important.

Knowing what is becoming important.

Legal regulations for fertilizers and sewage sludge lead to a need for action.
Knowledge about the pollution of our soils and waters by sewage sludge, as well as growing environmental and health awareness, have led to a rethink. After years of discussion, the legislature set the course in 2017 for far more environmentally conscious sewage sludge utilization.

The adapted Fertilizer Ordinance (DüMV) has implications for sewage sludge that can be used in agriculture. From the beginning of 2019, fertilizers containing synthetic polymers may only be used if the amount of synthetic polymers applied does not exceed 45 kilograms of active substance per hectare within three years. As a result, as of January 1, 2019, many sewage sludges can no longer be used as fertilizers.

The amendment to the Sewage Sludge Ordinance (AbfKlärV), which was also passed, also aims to reduce the agricultural use of sewage sludge and ensure phosphorus recovery. From 2029, phosphorus recovery will be mandatory for wastewater treatment plants with an expansion stage of at least 100,000 population equivalents (p.e.). Three years later, the same will apply to plants with a population equivalent of at least 50,000. The plants concerned treat around two-thirds of the wastewater generated in Germany.

For large sewage treatment plants, the Sewage Sludge Ordinance stipulates that, in addition to the obligation to recover phosphorus, there is also an obligation to dispose of it thermally. The phosphorus content of the sewage sludge must be reduced by at least 50 percent or to less than 20 grams per kilogram of dry matter.

The implementation of these regulations will result in an immediate need for action for many municipalities. As a partner of the municipalities, we are ready to develop tailor-made solutions for a pioneering resource-saving sewage sludge utilization. Particularly at existing EEW sites, useful synergies with existing waste incineration plants can be achieved.