On 4 September 2026, The Cool Down reported that Greece has moved a wastewater-recycling project at Markopoulo from a December 2025 inauguration toward broader use, with operators treating the sewage stream as a local irrigation source rather than sending it to a distant treatment plant.
Key takeaways
- Greece's sewer-mining project at Markopoulo was inaugurated in December 2025 by the Athens Water Supply and Sewerage Company and the National Technical University of Athens.
- The Markopoulo site uses membrane bioreactor technology together with ultraviolet treatment, plus solar power and digital monitoring.
- A Metamorfosi pilot was described in Athens Water Supply and Sewerage Company's sustainability reporting as "the first sewer mining application in Greece".
- Reclaimed water at the Goudi Park tree nursery met standards for unrestricted irrigation and urban use, the National Technical University of Athens said.
- The National Technical University of Athens' circular-economy water research program runs through 2028 and continues to operate and monitor the Athens nursery pilot.
What happened
The Markopoulo project, inaugurated in December 2025, was developed by the Athens Water Supply and Sewerage Company together with the National Technical University of Athens and cleans wastewater close to where it will be used, supplying reclaimed water for irrigating urban green areas, The Cool Down reported. The outlet cited Greek Reporter as the upstream source for the inauguration detail.
Two further Markopoulo-area projects are lined up. The first is a pilot in Metamorfosi that Athens Water Supply and Sewerage Company's sustainability reporting identified as "the first sewer mining application in Greece," and the second is the installation at the Athens Urban Tree Nursery in Goudi Park, according to 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.
Why a decentralized route
Sewer mining works on a smaller, decentralized scale than a conventional centralized treatment plant, which can reduce how far wastewater and freshwater need to be transported, The Cool Down reported. The outlet framed the rationale this way: by reserving drinking-quality water for cooking, drinking and hygiene, cities can stretch limited supplies further while still maintaining parks, trees and other greenery that helps cool neighborhoods during Greece's long, hot summers.
Markopoulo represents the most advanced stage of the work, combining membrane bioreactor technology with ultraviolet treatment and adding solar power and digital systems for monitoring and control, The Cool Down reported. The National Technical University of Athens' circular-economy water research program runs through 2028 and includes ongoing operation and monitoring of the Athens nursery pilot, the outlet added.
Specification read
The Markopoulo installation is described as the most advanced stage in the Greek program and combines membrane bioreactor (MBR) technology with ultraviolet disinfection, solar power and digital monitoring and control, according to The Cool Down. The source does not report a daily flow figure in cubic metres per day, a plant capacity, a population-equivalent value, a contract value or a project budget, so a buyer cannot pin a flow class to this specific site from the supplied text. Decentralized sewer-mining reuse schemes of this type typically operate at a small, neighbourhood scale, often in the order of tens to a few hundred cubic metres per day (general industry range, not from the sources).
For a buyer evaluating a similar decentralized reuse train, the relevant stages are fine screening, primary clarification or grit removal, biological treatment (an MBR is the technology named at Markopoulo and is the obvious reference for this class of urban irrigation reuse), and tertiary disinfection such as ultraviolet to meet unrestricted-irrigation reuse criteria, with digital monitoring and renewable-energy integration sitting across the train. This event bears on the biological MBR stage, the tertiary ultraviolet stage and the reuse-quality compliance bar for unrestricted urban irrigation. A membrane bioreactor skid sized for a defined municipal or commercial flow is the typical procurement package, with downstream water purification units handling the reuse-quality polish; readers can compare the MBR class against municipal reuse references and against related guides such as the DAF vs clarifier for mining wastewater in Fairbanks and the DAF vs clarifier for mining wastewater in Dorchester, US factory guides for the upstream primary-clarification decision.
For a plant manager or municipal engineer, the recognition is straightforward: if your facility handles a small-to-medium decentralized wastewater flow (rough class, low thousands of m³/day, BOD in the typical municipal range of roughly 150-400 mg/L, public green-space or urban landscape irrigation as the end use, and compliance pressure driven by drought or potable-water scarcity rather than heavy industrial discharge limits), then this is the kind of MBR plus ultraviolet, solar-assisted, digitally monitored skid package you would shortlist for an unrestricted-irrigation reuse permit.
FAQ
What flow class fits a Markopoulo-style decentralized sewer-mining unit?
The source does not report a flow figure. Decentralized sewer-mining reuse schemes of this class typically run at tens to a few hundred m³/day (general industry range, not from the sources), so an enquiry should be framed around a target m³/day and a target reuse end use rather than a population equivalent. (The Cool Down)
Which treatment stages does this event confirm as procurement-relevant?
The Markopoulo installation confirms membrane bioreactor biological treatment and ultraviolet disinfection as the core reuse train, with solar power and digital monitoring overlaid, so an enquiry should specify MBR membrane area, UV dose, a SCADA or telemetry package and a renewable-energy integration scope. (The Cool Down)
What reuse-quality bar did the Goudi Park reclaimed water meet?
The reported reuse bar at Goudi Park was standards for unrestricted irrigation and urban use, which typically maps to low BOD and TSS, tight turbidity, and validated disinfection at the ultraviolet stage; an enquiry should therefore ask suppliers for documented compliance with the relevant national or EU unrestricted-irrigation reuse criteria, not just a generic reuse claim. (The Cool Down)
What is the indicative lead time and supplier-selection focus for a skid of this class?
The source gives no lead time. For a packaged MBR plus ultraviolet skid of this class, a typical engineering-procurement-construction scope runs several months for fabrication, delivery and commissioning (general industry range, not from the sources), and supplier selection should weight documented reuse-quality compliance, membrane replacement cost, energy use including any solar integration, and remote-monitoring capability over headline capital cost.
