This project is submitted on the basis of a call for applications under procedure NoBG16M1OP002-1.006 “Implementation of early water and sewerage projects”. The project will ensure optimal disposal and treatment of waste water collected in collecting networks, which are currently discharged without adequate treatment to meet the requirements laid down in Directive 91/271/EEC. The following measures are included in this project proposal, which concern the sewerage network: replacement of 13.428 km of secondary sewerage network in order to reduce the infiltration flow to the waste water treatment plant (WWTP); rehabilitation of Main manifold VII and construction of a new manifold with a length of 2.746 km to ensure sufficient hydraulic capacity of the system. The approved conceptual project for reconstruction, modernisation and completion of WWTP — Plovdiv will reduce the flow of harmful substances and paint elements into the receiving water. Waste water treatment will allow for reliable and technologically sound compliance with European requirements for water released under cost-effective conditions. With the realisation of the project, the sludge treatment process will be optimised, including through sludge stabilisation, mechanical removal of water and thermal drying of the sludge and use of biogas.