In October 2014, the municipality of Kastoria and Alpha-Bioenergy agreed in the pilot application of bio-augmentation in the wastewater treatment facilities of the town. The application is continuing until today. The plant has an average flowrate of 8000 m3/d which is fluctuating due to heavy seasonal rains (12000-15000 m3/d). With the everyday use of BIO-M product and the change of some operational parameters, the plant achieved extremely low effluent values for TN, TP, BOD, COD, and TSS, much lower than the legislation limits. The samples were tested also in external laboratories. The plant occasionally receives particularly heavy wastewaters originating from tanneries, which they are now able to treat without compromising the effluent quality.