Before the Battle of Salamis in 480 BC, Persian forces settled on Psyttalia island. After the battle, the Persian fleet left and the Athenian general Aristides landed on Psyttalia island and killed the remaining Persian forces. Since the 1950s, Athens has struggled with sewage management. Makeshift cesspools and sewage tankers were initially used before a central sewer system was built in 1959, dumping untreated waste into the Saronic Gulf. By the 1980s, Greece was obligated under EU law to implement secondary wastewater treatment. Athens opened its wastewater treatment plant in 1985. Further projects were undertaken in the 1990s to expand sewage infrastructure to more of Athens and implement offshore wast