Monemvasia is located on a small island at the east coast of Peloponnese. This Medieval Castle Town, carved on the slopes of a rock, is one of the main touristic attractions in Greece. High temperature levels and increased population during the summer period caused severe odor emission problems originating from the sewer network. Application of bioaugmentation in the sewage collection system commenced in the summer of 2020 in Monemvasia castle, as well as in another three (3) settlements, namely Molaoi, Plitra and Neapoli and resulted in significant mitigation of the odor emission problems that were well documented until that time. After less than a month of application, malodorous gases production in sewer network has been successfully limited in all cases, as proven by analytical emission recording data, as well as civilians’ statements.