Psyttaleia (Greek: Ψυττάλεια) is an uninhabited island in the Saronic Gulf a few miles off the coast of Piraeus, Greece. It covers an area of 0.375 square kilometers. The island currently houses the largest sewage treatment plant in Europe, with a projected daily maximum drying capacity of 750 tons of sewage. Administratively it's part of the Municipality of Piraeus. History In 480 BC, before the naval battle of Salamis, the Persian… (More on Psyttaleia)