Psyttaleia sludge causes quite a stink

A series of delays and lack of funding have undermined the performance of the wastewater treatment plant at Psyttaleia, despite the occasional jubilant proclamations by YPEHODE. The unit has triggered a spate of reminders from the EU of its inadequate performance, chiefly due to the lack of secondary treatment units and treatment of the sludge that remains after cleaning. Neither jaunty advertising by YPEHODE nor the nihilistic picture painted by its critics tell the whole truth about Psyttaleia. The plant still does not operate biological purification systems but is confined to mechanical cleaning – which removes larger solid debris such as stones, bits of wood, earth, sand and inorganic substances larger than 2 centimeters in diameter that would otherwise end up in the Saronic Gulf. The head of the Psyttaleia sewage treatment works, Nikos Heimonas, said that «today, 33 to 40 percent of the wastewater is cleaned, a proportion that will rise to 90 percent with the commencement of secondary treatment.» Secondary treatment, which involves biological purification with microorganisms and oxygenation in order to eradicate bacteria, will probably undergo a test run at the end of this year. The unit will be fully operable in spring 2004. Nonetheless, Psyttaleia’s basic problem, treating the sludge that is a by-product of cleaning, will continue to trouble EYDAP for a long time to come. The agreement the water company has signed with the Union of Municipal Authorities in Attica (ESDKNA) provided for the transfer of 300 tons of sludge to the landfill at Ano Liosia. But this year’s landslide at the landfill led the local municipality of Ano Liosia to ban the transfer and dumping of the sludge. The sludge embargo lasted for three months, with the result that 20,000 tons of sludge collected on the islet, covered with a layer of lime to deal with the stench and the health hazard. «The problem of sludge is one that all sewage treatment plants have,» Heimonas acknowledged, referring to the application submitted by YPEHODE to the EU for funding for a sludge dewatering unit to shrink volume to 75 percent. According to experts, sludge that has been through secondary treatment could either be burned on the island (although political decision-making will not tolerate even «one new chimney in Attica») or used in agriculture as a soil fertilizer, after toxic substances are removed. The dean of Patras University’s technical school, Demetrios Papamantellos, pointed out in a letter to Kathimerini that «the city of Stockholm sends its sludge, by train, a distance of 1,500 kilometers (930 miles) to enrich the soil at copper mines.» Sludge can thus be used to restore the natural landscape. With the right treatment, said Heimonas, sludge could also be used as fuel in cement factories, as it is «95 percent organic and has a heat-generating capacity equivalent to that of lignite.»