The main goal of the project was to accommodate the additional outlet of wastewater from 342,500 citizens |
As part of the Kubratovo WWTP project, the six biotanks of the treatment plant, the primary sedimentation tanks and six of the eight secondary sedimentation tanks were renovated and two new secondary sedimentation tanks were constructed. The primary reconstruction activities for the treatment plant along the water flow consisted of reconstruction and refurbishment of the primary sedimentation tanks, including the replacement of mud cleaner bridges, reconstruction of the inner concrete surface of the sedimentation tanks, as well as a new booster system. This was because the sedimentation tanks are built on a modular construction principle with panels.
In addition, the power substation and the installation for reagent dosage are new. The reagent plant with metering pumps for ferric chloride dosage was built for the removal of phosphorous using ferric chloride. The installation consists of a building in which three tanks for ferric chloride are placed, each with a capacity of 70 m3. The dosage of the ferric chloride is carried out using three operating and one standby Grundfos dosing pumps. Five dosing pumps for ferric chloride were delivered for the reagent plant, each with a capacity of 375 l/h.
The treatment plant was equipped with control and measurement instruments, and a SCADA system for control of processes was installed. This ensures an automatic operation of the station, with the technological processes controlled and managed by the automated system.
The renovation project for the Novi Iskar SPS included reconstruction of the collectors, which consisted of their washing, cleaning and repair, cleaning of the pumping station and completion of the building, cultivation of the terrain and restoration of the pipeline to Kubratovo.
The pumping station was renovated and it now has entirely new equipment while keeping the original construction. The pumping station now has five big pumps; three for domestic wastewater (two operating and one standby) and two for surface water (one operating and one standby) were mounted.
All equipment for the Novi Iskar SPS, which includes pumps for domestic wastewater and surface water, was provided by Grundfos Bulgaria. It has two mixers in the draw tanks, which periodically stir the water to prevent the formation of crust and sludge. A small drainage pump was also mounted, which is used to pump water from leaks and so on out of the dry chamber where the pumps are installed, preventing flooding.
Author's note: Lenko Georgiev is the country manager for Grundfos Bulgaria.