Pau-Lescar Biofactory: the first wastewater treatment plant to recover CO₂ from sludge methanation

Pau Béarn Pyrénées metropolitan area has adopted a proactive environmental policy and aims to be carbon neutral by 2040. It means to boost renewable energy production.

As part of a unique initiative, Lescar wastewater treatment plant is now playing a key role in local climate change adaptation measures. This "resources and energy from wastewater" production plant becomes a "Biofactory" which will develop 10 resources and green energy sources, with a strong focus on synergies with the local Cap Ecologia environmental industry park.

This environmental showcase is part of an ambitious territorial project for the development of renewable energies while creating sustainable local employment.

The project includes two "global technology firsts" resulting in an energy-positive building and an unrivalled carbon footprint.

• Catalytic methanation. The site’s energy performance is increased by the production of synthetic methane from the methanation of carbon dioxide (CO₂, a greenhouse gas). For the first time in the world, this innovative catalytic methanation technology will transform all the CO₂ emitted into synthetic methane, a renewable green gas.
• "Ultra-dewatering" by hydrothermal carbonisation. This new technology divides treatment sludge volumes by four and consumes three to four times less energy than a conventional thermal dryer, while reducing the potential disruption associated with drying. This SUEZ-designed process considerably increases biomethane production and generates a new material resource, Biocoal, which can either be returned to the soil, or turned into energy through combustion.
  

Thanks to its cutting-edge architectural and landscaping design, the new anaerobic digestion and methanation facilities fit in perfectly with the existing wastewater treatment plant, which lies at the heart of Cap Ecologia environmental industry park.

An educational copse, flowered meadow and micro forest will help to restore the site's biodiversity.

Pollution prevention and advanced air treatment technologies ensure that there is no risk of odours nuisance for local residents.

An educational initiative will help to raise awareness of environmental transition issues among the general public and schoolchildren.

Through this unprecedented circular economy project, Lescar wastewater treatment plant is now playing a key role in the environmental transition and in local climate change adaptation measures.

Through its two global technology firsts and its implementation of low-energy processes, the wastewater treatment plant is now an energy-positive facility: it produces more energy than it consumes and has an unrivalled carbon footprint.

When the project is completed, the plant's emissions will be 50% lower than they are today. This enhances the site’s contribution to meeting the targets of the regional climate plan and carbon neutrality strategy. This carbon footprint is enriched by the production of new resources that avoid the emission of approximately 5,000 tons of CO₂ each year.

The plant is now an efficient local resource production facility using wastewater. Its short-circuit approach has a strong focus on synergies with the local Cap Ecologia environmental industry park, particularly the household waste to energy unit Valor Béarn and the future photovoltaic park.