place Case Studies

Athens, Greece

The Athens Nursery case focuses on the demonstration of innovative concepts of alternative water sources to reduce the use of freshwater resources, as well as integrated energy and nutrient recovery technologies on the transition to a CE-based water sector. In particular, the scope of the Athens pilot is to produce recycled water from urban wastewater with a sewer mining modular unit for urban green irrigation and other non-potable uses at the point of demand. The Athens Tree Nursery comprises 4 ha of vegetation, and supplies all urban parks and green spaces of Athens with plant material and uses potable water from Athens’s Water Supply and Sewerage Company (EYDAP) for its irrigation. Thus, the installation of a sewer mining (SM) modular unit for urban green irrigation at the point of demand has proven to be of direct benefit for the sustainability of the new metropolitan park of the capital. In particular, the SM technology is a decentralised, flexible and autonomous CE solution in which wastewater can be extracted locally from the sewers that run under any city, be treated directly on site and create valuable high quality reused water at the point of demand to be used for green spaces irrigation and for aquifer recharge during the winter.
Furthermore, the site was an ad hoc storage area for pruning waste from park maintenance activities across the city. Thus, the installation of a rapid composting technology in the site using excess dewatered sludge produced from the SM unit and treated pruning wastes from the nursery, is of direct benefit for the sustainability of the area. In particular, these two components (prunning and sludge) are being continuously mixed in a Rapid Composting Bioreactor, where the closed and aerated system speeds up the degradation process to create in approximately 2 weeks roughly 200 kg of high-quality compost as an on-site fertilizer to be applied on the place of demand (Nursery plants). In addition to water and nutrient recovery, a thermal recovery unit is also installed at the site to test energy recovery schemes through a heat exchanger and heat pump system, recovering approximately 15kWh of thermal energy from the treated wastewater. This heat is used to boost the Rapid Composting Bioreactor, for added system efficiency.
The overall goal is to create healthy and vibrant green spaces in the city of Athens. The pilot test shows that by upcycling two available waste streams: wastewater (& sludge) and green waste, Athens can have a sustainable solution for irrigation water and nutrient rich compost.

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Last update on 2022-03-29 10:57 UTC