This project will construct a Waste Water Treatment Plant with a 20-year capacity of 6000 equivalent inhabitants for the treatment of waste water from the settlements of Varda and Psari in the Municipality of Andravida Kyllini and, in the future, from the settlement of Nea Manolada with an active sludge system with prolonged ventilation and biological nitrogen removal b The remaining internal sewerage network in Varda with a length of 10050 m, the internal sewerage network in the settlement of Psari with a length of 4000 m, the necessary pipelines for the supply to the WWTP, a depressive section of the 530 m transmission pipeline for Varda and a depressive transmission pipeline with a length of 470 m for Psari and 2 pumping stations The works for the disposal of treated waste water in the sea area of the Gulf of Kyllini, a pipeline with a land section of 3570 m and a subsea section with a length of 1070 m.