The Thessaloniki Wastewater Treatment Plant (WWTP), located at the mouth of the Axios River, is one of the largest and most critical environmental facilities in Greece. It serves as the primary guardian of the Thermaic Gulf, processing the urban and industrial effluents of the entire Thessaloniki metropolitan area. NAMA played a central role in the facility’s evolution, delivering the process and detailed engineering design for its massive expansion to a capacity of 1,300,000 population equivalent (p.e.).
NAMA’s involvement ensured that the plant could handle a staggering final hydraulic capacity of 440,000 cubic meters per day, providing a robust solution for the region’s long-term environmental sustainability.
Integrated Engineering and Technological Innovation
The project was characterized by its multidisciplinary complexity, integrating advanced chemical engineering with heavy structural and mechanical design. Key technical features include:
- Comprehensive Treatment Cycle: The design covers the full spectrum of modern wastewater management, including advanced pretreatment, primary sedimentation, intermediate lifting, and a large-scale biological treatment phase.
- Industrial Waste Integration: A critical aspect of NAMA’s design was the plant's ability to receive and treat not only urban sewage but also complex industrial waste from the surrounding industrial zones.
- Circular Energy Management: To optimize the plant's carbon footprint, the design features a sophisticated sludge treatment system that includes anaerobic digestion. This process enables the regeneration of electric power and the production of biogas, which is used to meet a portion of the facility's energy needs.
- High-Level Automation: The entire complex operates via a fully automated network of PLCs (Programmable Logic Controllers) and a centralized SCADA system, allowing for real-time monitoring and precision control of all processing units.
Environmental Impact and Marine Restoration
The expansion of the Thessaloniki WWTP has had a transformative effect on the marine ecosystem of the Thermaic Gulf. By ensuring high-quality effluent discharge, the plant has contributed significantly to:
- Water Quality Improvement: A dramatic reduction in organic loads and nutrients, preventing eutrophication and protecting local biodiversity.
- Public Health Protection: Securing the safety of coastal waters for recreational use and supporting the local shellfishing and fishing industries.
- Urban Resilience: Providing the city with the infrastructure necessary to support further population and industrial growth while maintaining strict environmental compliance.
For NAMA, this project demonstrates our capacity to lead the design and supervision of large-scale utility projects. Our work at the Thessaloniki WWTP remains a benchmark for how integrated engineering can turn a major urban challenge into a sustainable resource for an entire region.
