At the Municipal WWTP of Heraklion in Crete, Greece, a retrofit and upgrade project was carried out to enhance wastewater treatment performance through the installation of a tertiary MBR stage. The system uses submersible membrane bioreactor technology to provide advanced treatment capacity of 6,000 m³/day, serving approximately 30,000 equivalent population. Delivered for DEYA Heraklion and installed in 2016, the project also included operation support, contributing to improved effluent quality and the modernization of the city’s wastewater treatment infrastructure.