Wastewater Sludge Recycling

Waste that has to be managed

Urban growth and the proliferation of wastewater treatment plants have sharply increased the production of municipal sludge worldwide. As an example, in France, more than 200 million metric tons of liquid sludge needs to be treated each year. Separated from its water which is discharged into the environment after treatment, sludge waste is treated in accordance with its end use.

Three recycling processes

Public authorities have three solutions to choose from when recycling wastewater sludge:

• Agricultural recycling. This yields plant nutrients, lime and carbon inputs that can be used to make humus or a concentrate of fertilizers supplemented as needed with commercial fertilizers.
• Landfilling. The sludge is mixed with municipal waste in landfills, where its anaerobic decomposition produces landfill gas recoverable as energy (heat and/or power).
• Incineration or co-incineration. Incineration, or gas-phase thermal oxidation, destroys organic matter, leaving a tiny amount of mineral byproducts. Sludge and municipal waste co-incineration and wet air oxidation—a process used for over 40 years in the United States that is starting to catch on in Europe—recover mineral materials most often recycled in public works construction, in road sublayers, backfill, pre-cast concrete, etc.

Proven experience

Involving a wide range of technological solutions, Veolia Water's services:

• Reduce the amount of sludge produced.
• Guarantee a high level of health security.
• Recycle sludge.
• Decrease odors.

To achieve the above objectives, we draw on years of experience operating and upgrading all kinds of treatment plants and leverage the talents of the employees of Veolia Water Solutions and Technologies and SEDE Environnement, a Veolia Water and Veolia Environmental Services subsidiary specializing in sludge management.