Co-incineration of sludge and domestic waste

Veolia Water Technologies and Veolia have pooled their expertise within CREED - Veolia's research centre serving the company's Energy Services and Waste Management divisions - to develop the Pyromix™ solution.


Pyromix™ injects pasty sludge directly into the waste incinerator using compressed air sprayed through an injection pipe inserted in the incinerator wall.



Using PYROMIX™ to feed a waste-to-energy plant with WWTP sludge

  • Injection of sludge at 15-25% DS content;
  • Up to 20% of household waste tonnage;
  • No impact on bottom ash quality;
  • No change in thermal capacity of the incinerator;
  • Easy incinerator operation (improved thermal stability);
  • Optimized steam generation;
  • Complete destruction of sludge.


With PYROMIX™ , facilities can be used for the co-incineration of all types of municipal waste.

The process thus offers an additional reclamation option for sludge disposal.


The air's pressure and flowrate are set to ensure an even dispersal of the sludge in the form of fine droplets over the domestic waste.

The sludge is incinerated with the waste, without:

  • increasing the production of waste gas treatment residue,
  • modifying the nature of the slag.


Up to an additional 20% (weight) of household waste can be allocated to sludge, without altering the thermal capacity of the incinerator.



  • Elimination of sludge drying phase;
  • No grab handling (direct spraying of sludge into the incinerator);
  • Sludge injected in the form of fine particles and evenly spread over the household waste;
  • Injector adaptable to all types of grate incinerators;
  • Easy maintenance (single injection system);
  • Simple installation and reduced investment cost;
  • Alternative option to basic sludge disposal outlets;
  • Sludge-to-energy recovery system.