The project includes the collection and the transfer of the sewage water of Koropi – Paiania municipalities in Attica Prefecture to the Waste Water Treatment Plant of Koropi – Paiania (Koropi KEL), the design and the construction of the Koropi KEL and the disposal of the treated sewage into the sea through a subsea pipeline. This project will be  serving 120.000 citizens.  

          The project includes the construction of the sewage pipelines inside Koropi town with total length ~81km, the construction of the collective pipelines which will cover the Koropi – Paiania municipalities and the main collective pipeline, which will concentrate the sewages of Koropi, Paiania, Karellas settlement, industrial areas and parks of Koropi – Paiania district and transport them to the KEL, with total length of 17,5km.

          The treated sewages of the new Koropi KEL, as well as the treated sewages of the existing Markopoulo KEL, will be being transported to the sea through new disposal pipelines with total length of 14,3km and a common new disposal pipeline with total length of 4,7km. 1,3km of the common pipeline will be constructed in tunnel with internal diameter 4m. Finally will be constructed a new subsea disposal pipeline for the whole quantity of the treated sewages, with total length 1km and max depth 55m.