Greece is advancing wastewater recycling as pressure on the country’s water resources grows, with treated water being recovered for uses such as irrigation.
The approach is being developed through a series of projects by the Athens Water Supply and Sewerage Company (EYDAP) and the National Technical University of Athens (NTUA), utilizing a technology known as sewer mining to recover water and reuse it locally. The latest project in Markopoulo, east of Athens, represents the most advanced publicly presented stage of a process that began years earlier with a pilot installation at EYDAP’s facilities in Metamorfosi.
The progression from a research experiment to a public installation powered by solar energy and equipped with digital monitoring shows how Greece is exploring ways to reduce its dependence on freshwater for uses that do not require drinking water.
Greece’s first sewer mining experiment
The story began at EYDAP’s Environmental Research and Development facility in Metamorfosi north of Athens. EYDAP’s sustainability reporting identifies the installation there as the first sewer mining application in Greece. Developed through the European DESSIN research program, the system was designed around local wastewater recycling to recover water for reuse.
The idea behind sewer mining differs from conventional centralized wastewater treatment. Rather than transporting all wastewater to a large treatment facility and then sending freshwater back to where it is needed, a decentralized system can treat sewer water close to the point of demand. EYDAP has described the approach as a way to reduce pressure on natural water resources while also limiting the need to transport wastewater (and water in general) over long distances.
The first installation was therefore a test of whether wastewater could be recovered locally and transformed into a useful water resource. The answer paved the way for further projects.
From research to Athens’ urban green space
The next stage brought the technology into a working urban environment. A sewer-mining installation was developed at the Athens Urban Tree Nursery in Goudi Park through the European NEXTGEN project, with the participation of the NTUA, EYDAP, and the Municipality of Athens among others. The system treated wastewater locally and produced reclaimed water for irrigation.
NTUA described the site as a “living lab,” where researchers could test circular-economy technologies under real urban conditions and examine how alternative water sources could reduce demand for freshwater. The project also explored the recovery and reuse of other resources from wastewater, reflecting the broader principle of the circular economy that materials and water that would normally be treated as waste can instead be recovered and put to productive use.
EYDAP later reported that the reclaimed water produced at the Athens nursery met the criteria for unrestricted irrigation and urban use. The project demonstrated that sewer mining could move beyond an experimental facility and operate in a public urban environment.
Athens, Greece suburb of Markopoulo advances wastewater recycling technology
The latest step came in December 2025, when EYDAP, NTUA, and the Municipality of Markopoulo–Mesogeas inaugurated a new decentralized water-recovery system. EYDAP describes it as the third sewer-mining system it has developed with NTUA, following the installations at its research facilities and the Athens municipal nursery.
The Markopoulo project advances wastewater recycling in Greece by producing reclaimed water for irrigating urban green spaces. The treatment system combines membrane bioreactor (MBR) technology with ultraviolet (UV) treatment. The installation also incorporates solar power and digital technology for monitoring and control.
NTUA has described the Markopoulo system as a scalable solution that could contribute to addressing water scarcity and strengthening climate resilience. The project therefore represents a significant evolution from the first Greek sewer-mining experiment. The basic principle remains the same—recover water from wastewater close to where it is needed—but the latest installation combines water recovery with renewable energy, digital monitoring, and public environmental education.
The reclaimed water is not potable water
It should be noted that the projects developed by EYDAP and NTUA are advancing wastewater recycling in Greece, but the reclaimed water will not be intended for household uses such as drinking, cooking, or personal hygiene. Non-potable uses, particularly irrigation of parks, urban greenery, and other appropriate applications, are the only designated uses, and this distinction is central to the value of wastewater recycling in Greece.
Not every use requires potable water, and drinking-quality supplies can instead be conserved for uses that require them. EYDAP has stated it is gradually developing ways to use treated wastewater for industrial purposes as well as for irrigation of urban green areas and agricultural land.
From three projects to a broader wastewater recycling strategy in Athens, Greece
The three sewer-mining installations illustrate a clear progression. Metamorfosi was the first Greek test. The Athens municipal nursery demonstrated how the technology could operate in an urban environment and provide water for greenery. Markopoulo has taken the concept further with a publicly accessible installation combining advanced treatment, renewable energy, and digital monitoring, and experts are continuing to study the technology.
NTUA’s current research program on circular-economy technologies for water-resource management runs through 2028 and includes continued operation, measurements, and monitoring of the pilot installation at the Athens nursery. EYDAP has also identified wastewater reuse as part of its broader approach to water management, particularly in Eastern Attica.
This does not mean that decentralized sewer mining is about to replace Athens’ conventional water infrastructure. The existing installations remain demonstration and pilot projects. However, they show that Greece is moving from simply discussing wastewater recycling to testing how it can work in real communities.
Why water reclamation matters for Greece
Greece is facing increasing pressure on its water resources, particularly as drought and higher temperatures affect water availability. For Athens and the wider Attica region, the challenge is not only finding additional sources of water but also making better use of the resources already available.
That is where reclaimed water can play a role. Whenever reclaimed water is used for an appropriate non-potable purpose, less drinking-quality water needs to be diverted to that use. The concept is particularly relevant for urban greenery. Parks and trees provide important environmental benefits in a densely populated city, but maintaining them can require substantial quantities of water during Greece’s hot and increasingly dry summers.
Sewer mining offers one potential way to maintain green spaces without relying entirely on valuable potable water. It also changes the way wastewater is viewed. Instead of being the final stage of a linear system—water is supplied, used, and then discarded—wastewater becomes the starting point for another cycle.
For EYDAP and NTUA, the path from Metamorfosi to Athens’ municipal nursery and, ultimately, to Markopoulo shows that the concept has already progressed through several stages of testing. The next question is whether technologies such as sewer mining can be scaled up sufficiently to become a meaningful part of Greece’s long-term response to water scarcity.
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