A ray of light in the dispute over the disposal of thousands of tons of treated sewage at the Ano Liosia landfill appeared yesterday when local officials were impressed by a system used to biodegrade sludge in Thessaloniki. Local and regional authorities from northwestern Athens conducted a tour of the Tagarades dump – at the invitation by Environment and Public Works Minister Giorgos Souflias – to see in action a method of disposing of treated sewage whereby it is mixed with earth, leaves and branches to allow it to biodegrade into fertile soil. Souflias has suggested that the same method could be used at Ano Liosia to help dispose of up to 150,000 tons of sludge that has built up at the Psyttaleia treatment plant. After their visit, the officials said the system seemed «reliable.» They were concerned, however, at how the technique would cope with the quantities of sludge – at least 800 tons a day – that would be treated at Ano Liosia. They said they would discuss the issue at a meeting on Wednesday, when they will also decide whether to close the landfill again.