pumpstations

a capital expansion

By Pavel Mirchev he Wastewater WWTP, which, up to that point Treatment Plant (WWTP) had been directly discharged into Tat Kubratovo—the larg- receiving waters. Furthermore, the Largest wastewater est wastewater treatment plant in entry of into the European the Balkans—treats the domes- Union (EU) made expansion of treatment plant in tic wastewater, process water and the Kubratovo WWTP necessary. rainwater from Sofia, the capital Bulgaria is obliged to comply with the Balkans receives of Bulgaria. Pumping 480,000 cu the EU’s urban wastewater direc- meters of wastewater from a pop- tive and national regulations for major refurbishment ulation equivalent of 1,313,000, emission norms for the allowable the Kubratovo WWTP meets the content of harmful and hazard- wastewater requirements of 90% of ous substances in wastewater dis- the city’s population. charged into receiving waters in Spread across 600 acres, the sensitive areas. Kubratovo WWTP began opera- tions in 1984. Two refurbishments Reconstructing & followed in 1990 and 2001, and on Modernizing Two Sites March 30, 2009, a massive refur- The two main aspects of the bishment and expansion project for project involved the reconstruc- the plant commenced. tion and modernization of the Grundfos was a primary con- Sofia WWTP at Kubratovo and the tractor and contributed equip- construction of a sewerage pump- ment, technology, and project and ing station (SPS) and a pressure logistics know-how; the project was collector in Novi district. brought in on time and as planned The project was carried out by 20 months later, at the end of 2010. the Kubratovo Consortium, which The main goal of the project included contractors, system was to accommodate the addi- design consultants and suppliers. tional outlet of wastewater from A project of this scale had not Pump diffuser bed 342,500 citizens to the Kubratovo previously been undertaken in

6 Pump Source Fall 2013 www.wwDmag.com/pumps The renovated pumping station now has entirely new equipment, while keeping its original construction.

Bulgaria. Therefore, the contractor pipes with nominal diameter of 600 technological processes controlled needed a partner that offered the mm and a total length of 5.6 km. and managed by the automated technological and logistical support system. necessary, and knowledge about the Kubratovo WWTP processes. As the main equipment For the modernization of the Novi Iskar SPS provider, Grundfos ensured com- Kubratovo WWTP, four primary The renovation project for the pliance with deadlines, quality of sedimentation tanks, six biotanks, Novi Iskar SPS included recon- the equipment and installations at six secondary sedimentation tanks, structing the collectors through handover, and warranty support. and mud and floating substances washing, cleaning and repair, The project was carried out on pits were refurbished and recon- cleaning the pumping station and schedule, without delays result- structed. Additionally, two new completing the building, cultivat- ing from delivery problems. The secondary sedimentation tanks, ing the terrain and restoring the required working parameters for a pumping station for recircula- pipeline to Kubratovo. the Kubratovo installation were tion of active sludge, a mud water The renovated pumping sta- reached three months after its com- tank, a reagent plant and a power tion now has entirely new equip- missioning; the time was needed to substation were built. Additional ment, while keeping the original adjust the system and its operation. underground infrastructure more construction. It has five big pumps; During the execution of the than 4 km in length was also cre- three for domestic wastewater project, it was important that the ated, including pipeline for process (two operating and one standby) reconstruction and expansion of water ranging from nominal diam- and two for surface water (one the treatment plant was carried eters of 300 to 1,800 mm. operating and one standby) were out without halting the purification The reagent plant with meter- mounted. The pumping station processes for wastewater entering ing pumps for ferric chloride dos- also has two mixers in the draw the plant. This required the consor- ing was built for the removal of tanks, which periodically stir the tium to work with extreme flexibil- phosphorous. The installation con- water to prevent the formation of ity, as purification standards had to sists of a building in which three crust and sludge. be maintained at all times, mean- tanks for ferric chloride are placed, A small drainage pump also was ing, for example, that the receiving each with a capacity of 70 cu mounted; it is used to pump water water source—the Iskar River—was meters. The ferric chloride is dosed from leaks out of the dry chamber not to be polluted. using three operating and one where the pumps are installed, pre- The second group of activities standby Grundfos dosing pumps. venting flooding. All equipment for covered the reconstruction of the In total, five dosing pumps for fer- the Novi Iskar SPS, which included Novi Iskar SPS and the refurbish- ric chloride were delivered for the pumps for domestic wastewater ment of the sewer collectors in the reagent plant, each with a capacity and surface water, was provided by region. After the completion of the of 375 liters per hour. Grundfos Bulgaria. PS planned construction work, the The treatment plant was capacity was increased to a maxi- equipped with control and mea- Pavel Mirchev is external sales engineer mum rainwater flow of 850 liters surement instruments, and a for Grundfos Bulgaria. Mirchev can be per second. Additionally, 5 km of SCADA system was built for con- reached at [email protected]. sewer collectors in the town of Novi trol of the technological pro- Iskar were refurbished and a ris- cesses. This ensures automatic For more information, write in 1201 on this ing main was built using fiberglass operation of the station, with the issue’s reader service form on page 14.

www.wwDmag.com/pumps Pump Source Fall 2013 7