Lisbon - Frielas

Frielas Water Factory - Lisbon

The Frielas Water Factory, near Lisbon, is set to become a modern regional solids treatment centre with the introduction of Cambi's thermal hydrolysis process (THP). The project will increase renewable energy production, reduce biosolids volumes and support sustainable sludge management for more than one million people.

Operated by Águas do Tejo Atlântico, Frielas Water Factory currently serves more than 245,000 people in the Greater Lisbon area.

As part of a regional sludge management strategy, Frielas will also receive sludge from the nearby Alcântara and Alverca water factories, increasing its treatment capacity to serve more than one million people.

The challenge is to accommodate these additional sludge volumes without constructing new anaerobic digesters, while improving energy recovery and reducing the amount of biosolids requiring final management.

By integrating Cambi's thermal hydrolysis technology before anaerobic digestion, Frielas will be able to process significantly more sludge using its existing digestion infrastructure.

THP will also increase biogas production, particularly by enabling energy recovery from sludge imported from Alcântara and Alverca, where biogas is not currently produced.

The additional biogas will support renewable electricity generation, improving the facility's energy self-sufficiency and reducing its reliance on external energy sources.

Thermal hydrolysis will also improve sludge dewatering, reducing the final biosolids volume by approximately 50%. The resulting sterilised, low-odour biosolids will be better suited for agricultural use, supporting nutrient recycling and the local circular economy.

Expected project benefits

• Increased treatment capacity: Regional sludge treatment for more than one million people without additional digestion capacity.
• More renewable energy: Additional green electricity equivalent to the annual demand of over 6,000 Portuguese households.
• Approximately 50% less biosolids: Improved dewatering significantly reduces final biosolids volumes.
• Improved biosolids quality: Sterilised, low-odour biosolids better suited for land application.
• Greater energy self-sufficiency: Increased biogas production strengthens renewable energy recovery at Frielas.

The Frielas project marks the first implementation of Cambi's thermal hydrolysis technology in Portugal.

By combining regional sludge treatment, increased renewable energy production and improved biosolids quality, the project will help Águas do Tejo Atlântico establish a more resource-efficient and sustainable approach to sludge management in the Greater Lisbon area.

The Cambi THP system is scheduled for delivery in 2028.