ATHOS process

In France, 1.1million tons of sludge (i.e. roughly 22kg per person) is indirectly and unknowingly produced each year by consuming drinking water which, once used, is transported to wastewater treatment plants. This water treatment produces waste in the form of sludge. However, the solutions available to treat this type of waste are not adapted to all local authorities.

In the 1990s, Veolia's R&D launched research programs aimed at inventing economically and ecologically viable wastewater sludge treatment technologies.
This was achieved by the ATHOS process which uses a hydro-thermal oxidation technique(HTO).

The sludge generated by industrial and urban wastewater has become a genuine issue since the early 90s. This raising awareness coincided with the reinforcement of the legislation.

Thermal treatment, landfilling and economic recovery are the three solutions to the urban sludge problem but these solutions cannot apply everywhere, for regulatory, geographical or agricultural reasons.

In 1990 Veolia's R&D researchers identified existing technologies which could be adapted to the specific urban sludge issue. In 1996, following a long testing and adaptation phase, a pilot system was built in Veolia's water research Center in order to validate process engineering and viability. In 1998, a pre-industrial pilot unit was built in order to safely complete the industrial operation phase.

The European Community funded part of the project as part of the "Life Environment" program. In France, ADEME[1] and water authorities also supported the project.
The Veolia Water and Solutions and Technologies Division, the Technical Division and R&D worked together for four years to implement a prototype in Toulouse demonstrating the possibility of operating this process on an industrial scale.

Recognition came in 2002 with the city of Brussels' decision to acquire the 1^st wastewater treatment plant including the ATHOS hydro-thermal oxidation process.

[1] Agency for the Environment and Energy Management