The goal of Carborem is to reduce and valorise sewage and industrial sludges by means of a new generation technology known as HydroThermal Conversion (HTC). HTC allows the reduction of sludge volume to dispose of up to 90% and it converts the sludge into:

  • A liquid exploitable directly by means of anaerobic digestion process in order to produce biogas
  • A sterilised carbonaceous solid.

Carborem process concentrates some nutrients of the sludge (such as minerals, phosphorus and nitrogen) into the solid, giving to it some good properties for the use as soil improver.

Other ways to give a second life to the solid are:

  • As a filler for the production of paperboard for packaging
  • As secondary raw material for the production of struvite (a mineral fertiliser)
  • As a secondary raw material for the production of activated carbon or bio-fuel (especially jet-fuel SAF, or maritime fuel)

Using Carborem technology, the wastewater treatment plants and anaerobic digestion plants’ operators would profit both from the increase of biogas production (and possibly biomethane) from the HTC liquid and, from the elimination of disposal costs of the sludge if the solid product (namely hydrochar) is exploited as a secondary raw material.

HTC allows sewage sludge and digestate final disposal to be closed in an innovative way in the logic of zero waste and the circular economy.

The main strengths of the technology can be summarized as follows:

  • Reduction of the dry matter of sludge and digestate
  • Reuse of the liquid product for the production of biogas (and possibly for upgrading to biomethane)
  • Improved dewaterability of the obtained solid
  • Sterilization of the solid product with excellent properties as soil improver
  • Recovery of ammonia as ammonium sulphate
  • Recovery of phosphorus and heavy metals from hydrochar, by adding an additional purification module in the system