Performance of Urban Wastewater Treatment of Four Activate Sludge Treatment Plants in Tunisia

In water-scarce regions, such as Tunisia which is known by the vulnerability of its water resources, national policy encourages and imposes laws opting for environmental sustainability and the preservation of water resources. The current study aims to determine the occurrence and removal of protozoan cysts, helminthes eggs, fecal bacteria, organic load and chemical pollution in the urban wastewater of activated sludge plants in Tunisia. The results show that the absence of primary sedimentation and operation of organic and fluid overload appears to be the main causes of the poor quality of the treated wastewater. The presence of protozoan cysts, helminthes eggs and bacteria as well as the high content of organic matter and nutrient elements greatly limits the reuse of wastewater in agriculture, in particular.