A novel technology of the aerobic meso-thermophilic fermentation process for the optimal separation of sludge at WWTP, in terms of energy, has been developed. During the thermal sedimentation, viscosity of colloidal micelles is reduced, allowing the sludge to be separated from an amount (about 60-65%) of free water. As a result of using this technology, the sludge water (50% or more of the

sediment volume) is fed to the dilution of incoming wastewater to the head of the treatment plant, while the organic part (30-35% of the volume of sediment) is sent to microbiological processing either into biofertilizers or into microbial biomass used, for example, as enzyme feed additives, and the mineral part is removed to sand or silt areas. As a result of implementing the developed technology, the following social and economic benefits have been attained: 1. Reduction of the nuisance generated by the sludge: elimination of the odor, improving air quality: 2. Sludge reduction in volume (by 1/3) for storage: 3. Processing organic sediment (where heavy metal concentrations do not exceed MAC) in microbial biomass for the production of bio-fertilizer (an organic product for agriculture): 4. Decrease in energy consumption: by 12% in average. 5. The use of vegetal and mineral waste has been improved the efficiency of the purification process and the efficiency of sewage sludge separation in the sludge.