New energy from sewage sludge and animal meal - does this work?

Yes, with us it does, because not only coal, gas and oil can be burned in a steam generator. We also generate electricity from sewage sludge and animal meal. How? Very simple: We mix the normal coal we use with a small amount of so-called substitute fuels such as sewage sludge. In this manner we do not only save the precious primary energy source coal, but we simultaneously reduce the discharge of carbon dioxide. In addition, we at the same time solve the problem of how these substances can be put to a sensible use.

The situation

The sewage sludges arising in sewage plants have to be disposed of in an environmentally friendly, economic and safe manner. The population’s acceptance of its use in agriculture is increasingly dwindling, as the pollutants contained in sewage sludge can get into the food chain.

The possibilities

The alternative is combustion, as it meets the criteria of an environmentally friendly and economic disposal. The harmful substances contained in the sewage sludge are transformed into energy in the process. However, to burn exclusively sewage sludge is very expensive. In contrast, it is more cost-effective if the sewage sludge is burned along in coal fired power stations. These only need to be supplemented by the components required for the receipt, storage and conveyance of the sewage sludge.

For the sake of the environment

Co-combustion is an environmentally friendly method.

• The organic pollutants contained in the sewage sludge, among others also dioxins and furans, are completely destroyed during the combustion at temperatures in excess of 1,000 degree.
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• Inorganic pollutants such as heavy metals are predominantly bound in the ashes of the burnt coal, so that they can no longer reach the food chain.
  
  
• The ash and gypsum that are generated during flue gas purification are used as resources in the construction materials industry, keeping in mind stringent quality criteria.
  
  
• The flue gas purification plants are regularly inspected by neutral assessors and adhere to the strict thresholds of the 17^th Federal Imission Control Ordinance applicable to co-combustion.
  
  
• Another advantage for the environment: due to the use of sewage sludge and other substitute fuels, less coal is needed – the CO₂ discharge is reduced.
  
  

Sewage sludge co-combustion at E.ON Kraftwerke

E.ON Kraftwerke does not only procure substitute fuels for their own, but also for external power stations – Europe wide. For many years, our company has been involved in this field, with sewage sludge being the most important substance in this regard. But animal meal and paper sludge are also used. We permanently investigate the use of further substitute fuels and the development of further power station capacities, especially with regard to the co-combustion of sewage sludge.

For the sewage plant operators we offer individual and customised service packages – irrespective of whether we are dealing with communal or industrial sewage sludge, whether it is dried, partially dried or dehydrated, contaminated or uncontaminated. Year-round disposal, also for the long term, is at any rate guaranteed, as a multitude of power stations are available for co-combustion at E.ON Kraftwerke.

The specially set up substitute fuel division demonstrates the importance within the company.