TOP® - Wet Oxidation for Sludge Technology overview

3V Green Eagle's TOP® - Wet Oxidation for Sludge technology can achieve:

  • A significant reduction in sludge volume
  • The stabilization of sludge and dissolved metals
  • The removal of the microbial load
  • The partial or full mineralization of the sludge
  • A zero discharge process without the use of hazardous gases

Technology recognition

Since 3V Green Eagle commenced the implementation of its wet oxidation technologies in 1990, our treatment processes have received notable awards and international recognition which include:

  • The TOP® and Dual TOP® technologies were recognized as the "Best Available Techniques" for Wastewater and Sludge Treatment by the EU-IPPC Commission in 2006.

  • 3V Green Eagle is currently participating in the EU-funded ROUTES project where the effect of different operating parameters (i.e. temperatures, reaction time, oxygen dosage) are being investigated on the efficiencies of the TOP® and Dual TOP® technologies if it were to be scaled on an industrial level. Its ability to treat different types of sludge is also being studied.

Since the TOP® - Wet Oxidation for Sludge technology has been implemented on an industrial scale, 3V Green Eagle has observed that this treatment process can achieve the following:

  • The organic fraction constituted by volatile solid substances can be eliminated by up to 96%. This means that our technology has the capacity to almost entirely eliminate organic substances.
  • The operating conditions, including temperature and pressure, are more moderate and safer than those used for the TOP® - Wet Oxidation for wastewater technology.
  • The TOP® unit effluent is sent to the biological plant for final treatment.
  • A zero discharge process is established which does not produce any solid waste and no air emissions
  • This treatment process can eliminate almost all of the organic fraction which produces a stable, inorganic material that is rich in calcium and phosphorous. This material can also be reused as a primary-secondary material. In 2013, our solid residue obtained the CE mark which allows it to be used as a filler for bituminous materials and similar matters. Both the CE mark certificate and the TOP® Process Layout are available for download below.


The TOP® - Wet Oxidation for Sludge technology is able to treat sludge produced by biological systems at diverse operating conditions.

  • 2-3% in solid, directly following aerobic or anaerobic digestion and sent to TOP® via pipe
  • 15-25% in solid, after filter-pressing or centrifuging and sent to TOP® via truck or train.

Therefore, the TOP® - Wet Oxidation for Sludge can be installed at:

  • Large municipal facilities in order to treat sewage sludge produced by large biological plants.
  • Large industrial parks with multiple industries performing wastewater pre-treatment, generating large quantities of sludge following physical-chemical-biological treatment.

The industrial applications of this technology include:

  • Like the TOP® - Wet Oxidation for wastewater technology, the TOP® - Wet Oxidation for sludge technology has been widely tested on an industrial scale at 3V Green Eagle's facility in Grassobbio.
  • 3V Green Eagle is in a position to conduct feasibility studies and provide estimates of set-up and running costs for customized systems designed to meet its clients' specific requirements.
  • 3V Green Eagle is also able to offer Turn-Key plant systems or single process steps of the systems, integrating, in either case, this new technology with the client's existing facilities.