Microbiological quality of sewage sludge in Greece disposed for agricultural use.

For the disposal of sewage, sludge landfill is currently the practice adopted in Greece. Thirteen wastewater treatment plants located throughout Greece (islands excluded) were investigated over a period of 1 year in order to determine sludge microbiological quality. The time of exposure of the samples to environmental conditions and stress varied considerably, from a few hours to several months.