Athos™ is a sludge Hydro-Thermal Oxidation (HTO) process, which turns organic sludge with low dry matter into an essentially solid mineral.
Athos™ is an innovative process, which combined with anaerobic digestion, enables sludge removal while producing a renewable energy source: biogas.
Athos™ generates 3 stable and/or recyclable by-products:
- clean gas
- organic liquid biodegradable by traditional water treatment
- mineral-based inert solid
Features & Benefits
The Athos™ process complies with all regulations on the disposal of wastewater treatment sludge whilst remaining cost-effective. It benefits from the technological expertise and track-records of the Veolia Group, the world leader in municipal and industrial water treatment.
An environmentally friendly process
Athos™ is a clean technology: all the sludge components are recycled, recovered or discharged to the natural environment with no adverse effects.
- Final result: a concentrate of mineral matter accounting for only 1% to 2% of the quantity of initial liquid sludge;
- Possibility of recycling the technosand for building materials;
- Stabilization of the heavy metals in the solid residue in a non-leachable form (inert waste);
- Zero emission of polluted gases nor harmful by-products (nitrogen oxides, dioxins, furans);
- Reduction of greenhouse gas emission (50% drop in CO2 emissions compared with incineration;
- Destruction of toxic, malodorous (Hydrogen sulfide, mercaptan, etc.) and organic trace substances.
A cost-effective thermal process
Operating costs are reduced by:
- Moderate operating conditions (temperature and pressure, limited O2 consumption);
- Reducing the dewatering stage. The dewatering of oxidation residual doesn't require reagents and reaches 50% of dryness.
A flexible process
Athos™ provides high operational flexibility:
- Treats all types of thickened sludge (7 to 8% of DS);
- Possibility of adjusting retention time, temperature and oxygen flow, in accordance with sludge composition;
- Equipped with advanced automation.
A compact process
Thanks to its compact design, Athos™ can be fully integrated into the wastewater treatment plant and provides continuous sludge processing, as well as by-product treatment.
Athos™ treats all types of thickened sludge :
P.E.: Population Equivalent
|Trucazzanno, Italy||2004||300,000 PE|
|Epernay, France||2006||80,000 PE|
|Brussels North, Belgium||2008||
1.2 Million PE
|Aix-en-Provence, France||2011||175,000 PE|
|Rennes Beaurade, France||2012||360,000 PE|
With less than one-hour retention time in the reactor, the Athos™ process results in:
- Continuous and safe oxidation, under continuous mixing;
- High mineralization (less than 5% organic carbon content in the solid residue);
- Separation between liquid and mineral phases;
- Easily biodegradable liquid sidestream.
The heat released by the oxidation reaction is recovered to pre-heat the sludge, with no external energy supply.
Hydro-Thermal oxidation prototype: Athos™