Greece has inaugurated a wastewater-recycling project in Markopoulo that treats sewage close to where it will be used and delivers reclaimed water for irrigating urban green spaces, in a programme reported on 7 September 2026 (The Cool Down). The facility is the most advanced of two sewer-mining pilots developed by the Athens Water Supply and Sewerage Company together with the National Technical University of Athens (The Cool Down).
Key takeaways
- The Markopoulo plant was inaugurated in December 2025 by the Athens Water Supply and Sewerage Company and the National Technical University of Athens (The Cool Down).
- A pilot in Metamorfosi was identified by Athens Water Supply and Sewerage Company sustainability reporting as "the first sewer mining application in Greece" (The Cool Down).
- Reclaimed water at Goudi Park met standards for unrestricted irrigation and urban use, the National Technical University of Athens told the outlet (The Cool Down).
- Markopoulo pairs membrane bioreactor technology with ultraviolet treatment, solar power and digital monitoring and control (The Cool Down).
- The university's circular-economy water research programme runs through 2028 and includes ongoing operation and monitoring of the Athens nursery pilot (The Cool Down).
What happened
A second-generation sewer-mining site
The Markopoulo project, inaugurated in December 2025, represents the most advanced stage of the Athens Water Supply and Sewerage Company's sewer-mining work and uses membrane bioreactor technology alongside ultraviolet treatment, with solar power and digital systems for monitoring and control built in (The Cool Down). Rather than relying on a distant treatment plant, the system cleans wastewater close to where it will be used and supplies reclaimed water for irrigating urban green areas (The Cool Down).
From Metamorfosi to Goudi
Markopoulo sits alongside two earlier projects: a pilot in Metamorfosi that the Athens Water Supply and Sewerage Company's sustainability reporting identified as "the first sewer mining application in Greece," and the installation at the Athens Urban Tree Nursery in Goudi Park (The Cool Down). The National Technical University of Athens described the Goudi site as a "living lab" for testing circular-economy ideas in everyday urban conditions, not just for treating water, and said the reclaimed water met standards for unrestricted irrigation and urban use (The Cool Down). The university's circular-economy water research programme runs through 2028 and continues to operate and monitor the Athens nursery pilot (The Cool Down).
Specification read
The source does not publish a flow rate, population equivalent or treated volume for Markopoulo, so the headline figure cannot be restated in cubic metres per day from the reporting (The Cool Down). Decentralised sewer-mining systems of the class described here — a satellite membrane bioreactor paired with ultraviolet disinfection and a renewable-plus-instrumentation layer sized to a single neighbourhood demand — typically run in the low-thousands of cubic metres per day, with the bulk of the flow drawn from a small-diameter sewer trunk and reused for landscape irrigation (general industry range, not from the sources). The treatment train this class of project implies is screening, then biological treatment in the membrane bioreactor reported at Markopoulo, followed by ultraviolet disinfection and a digital monitoring and control layer, with solar offsetting part of the parasitic load; in effect it is a packaged Mbr Membrane Systems skid followed by a Water Purification UV stage, sitting outside a Municipal conventional plant. For readers comparing on the same page, related factory guides cover DAF vs Clarifier for Mining Wastewater in Detroit Lakes, MN: 2026 Factory Guide and DAF vs Clarifier for Mining/Metals Wastewater in Nome, US: 2026 Factory Guide. If your plant sits in the low thousand m³/day range, handles municipal-strength sewage (BOD in the 200-400 mg/L range, general industry range, not from the sources) and needs a non-potable reuse stream that meets unrestricted irrigation standards without tying into a trunk main, a Markopoulo-class MBR-plus-UV satellite is the configuration this event bears on, and it tells a procurement team to scope the membrane skid, the UV bank and the monitoring layer as a single packaged line rather than three separate purchases.
FAQ
What is sewer mining and how is it different from a conventional treatment plant? Sewer mining taps a sewer upstream of a central works, treats the flow with a small, decentralised package — at Markopoulo a membrane bioreactor with ultraviolet disinfection — and delivers reclaimed water for nearby use such as irrigation, instead of conveying sewage to a distant plant (The Cool Down).
What reuse standard did the Goudi Park reclaimed water meet? The National Technical University of Athens said the Goudi Park effluent met standards for unrestricted irrigation and urban use (The Cool Down).
Is the Athens Water Supply and Sewerage Company replacing its central network with sewer mining? No. The projects are still pilots and demonstrations, not replacements for Athens' conventional water network, but the company sees wastewater reuse as one part of its wider water-management strategy in Eastern Attica (The Cool Down).
How long will the research programme supporting the pilots continue? The National Technical University of Athens' circular-economy water research programme runs through 2028 and includes ongoing operation and monitoring of the Athens nursery pilot (The Cool Down).
