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Environmental approach in the HPP Kositsa

Stroitelna Mehanizatsiya AD starts work on the pressure pipe supplying “Kositsa” Hydroelectric Power Plant in the area the village of Divchovoto, municipality of Teteven. As a result of many years of operation, the facility needs urgent rehabilitation.

“Kositsa” HPP was designed in 2004 and put into operation in 2006. It is located in the Teteven Balkan, in a protected ecological zone Natura 2000. At present, the facility is not able to supply the design power despite the available water flow at the catchment area.

After inspection with a CCTV camera, corrosion on the inside of the steel pipe and some other problems have been detected, which lead to a decrease of pressure in the system as well as of water flow rate and thus to a decrease of the plant's productivity.

The pressure pipe is approximately 2400 m long, of which 400 m are made of PEHD with DN 450 mm. The rest of the pipeline is made of steel pipes with DN 420mm. The minimum depth of the pipe relative to the upper generatrix is 0.80m and the maximum - is 1.70m. Part of the pressure pipe is located in an extremely steep section with a drop of 45 meters between both ends of the sloping portion, where access of specialized equipment is impossible.

It is envisaged that Stroitelna Mehanizatsiya AD will apply a modern ecological approach for the complete restoration of the functionality of the facility, which includes the cleaning of the inside of the pipe, using specialized modern equipment, and subsequently rehabilitation by trenchless technology. These activities will extend the life of the pipe by 50 years or more and the operation of the plant with full capacity will be ensured.