Since the 1990s, the Saronic Gulf was starting to become polluted by industrial and residential sewage from Athens.
In order to protect the ecosystem and due to considerations for negative implications on tourism, a sewage treatment plant was installed on the island which started operation on November 1994.
This included the primary treatment, which prevents the waste from entering the sea, but did not provide a permanent solution for the resulting sludge.
Temporary solutions of exporting the sludge and of neutralizing it through oxidization proved insufficient over the years.

On June 1, 2007, the sludge treatment plant was put into operation, with two production lines of a total waste drying capacity of 500 tons per day.
Another two production lines started operation a month later, raising the total capacity to more than 750 tons per day.
It is estimated that the remaining sludge of 150,000 to 160,000 tons that was accumulated on the island over the years when only the primary treatment was active, would be converted to biofuel in the first six months of operation, and used in industry, especially in cement kilns and electricity power plants.
On October 5, 2007, environment vice-minister Themistoklis Xanthopoulos announced that there would be no sludge left in the following five months, and that auditors such as the European Court of Auditors had approved the quality of the plant.
Since the 1990s, the Saronic Gulf was starting to become polluted by industrial and residential sewage from Athens. In order to protect the ecosystem and due to considerations for negative implications on tourism, a sewage treatment plant was installed on the island which started operation on November 1994. This included the primary treatment, which prevents the waste from entering the sea, but did not provide a permanent solution for the resulting sludge. Temporary solutions of exporting the sludge and of neutralizing it through oxidization proved insufficient over the years.
On June 1, 2007, the sludge treatment plant was put into operation, with two production lines of a total waste drying capacity of 500 tons per day. Another two production lines started operation a month later, raising the total capacity to more than 750 tons per day. It is estimated that the remaining sludge of 150,000 to 160,000 tons that was accumulated on the island over the years when only the primary treatment was active, would be converted to biofuel in the first six months of operation, and used in industry, especially in cement kilns and electricity power plants. On October 5, 2007, environment vice-minister Themistoklis Xanthopoulos announced that there would be no sludge left in the following five months, and that auditors such as the European Court of Auditors had approved the quality of the plant.
Psyttaleia