Our advanced treatment systems help SUEZ customers manage and recover energy from biosolids, while meeting tightening discharge requirements. Exploiting advances in microbiology and other technologies, we design and construct comprehensive solutions – from anaerobic digestion to thermal oxidation.

Designed to recycle biosolids into methane and valuable by-products, SUEZ’s advanced anaerobic digestion technologies use bacteria in the absence of oxygen to break down matter to create biogas.


This biogas can be combusted or oxidised and used for heating, or – with a CHP (combined heat and power) engine – to produce electricity and heat. Biogas can also be compressed and used as fuel for vehicles.


The cake by-product is also put to good use as a fertiliser.


SUEZ’s dewatering equipment reduces sludge bulk by up to 30% compared to conventional dewatering. Our solutions confer various advantages, including increased productivity, high dry content, and lower operating costs.


We have developed a range of dewatering and drying systems.

Boost sludge dewatering with a piston press

The SUEZ Dehydris Twist unit increases productivity and can operate automatically 24/7, while delivering high dry content.


Based on the Bucher Unipektin piston press, it can be fed either with drinking water sludge or pre-thickened wastewater sludge conditioned with reagents (polymers possibly mixed with mineral reagents).


The Dehydris Twist is an enclosed and easy-to-operate industrial process, and reduces sludge bulk by up to 30%.

Thermal drying

Various methods can be used to reduce the volume and improve the quality of wastewater biosolids, including thermal and solar drying. Drying sludge can also transform this waste product into useful by-products or green fuel.


SUEZ provides a range of dryers producing safe and hygienic biosolids that are biologically stable. They allow for long-term storage as well as resource recovery.


Intrinsically safe, our low-temperature dryer outputs a low-density granulated product that is easy to reuse in energy production or agriculture. This highly efficient technology reduces sludge volume by up to 70%.

Thermal oxidation

Scarcity of land and more stringent sludge handling regulations are making fluid bed incineration more attractive for sludge disposal.


SUEZ’s thermal oxidation technology eliminates odours and reduces the sludge to a much smaller quantity of inert ash (as low as 7% by weight).


A highly efficient process, thermal oxidation maximises heat recovery. The physical footprint of a facility and emissions of pollutants are reduced, protecting the environment.

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