Molecor has recently completed a major project: that of supplying the Bulgarian city of Pernik with drinking water. This city suffered extreme drought since November 2019. The absence of rain and the very low water level in the Studena dam, with 25 million cubic meters of capacity, threatened to leave a population of 100,000 people without potable water.
In addition to the scarcity of flow from the Struma river that supplies the Studena dam, there were also enormous losses of water from the current installed pipes, estimated in more than 75% by the Water and Sewerage Systems of the city. That is until the installation of the new line with the TOM® PVC-O pipes of Molecor, three-quarters of the water extracted from the dam did not reach the inhabitants of Pernik. This situation, which has put Pernik into the spotlight of all the Bulgarian national media and of a multitude of international media, led the city authorities to implement extraordinary measures to ensure the supply to the population, which was already suffering severe daily water cuts, 6 hours of water a day and 18 hours without supply.
These measures implied the installation in record time, of a new drinking water supply line of 12,5 km in length, which would connect and reinforce, with a capacity of 300 l/sec, the supply of Pernik. After making the necessary calculations, it was confirmed that the city could be supplied from the Belmeken dam, which supplies the capital of the country, Sofia, which could absorb these needs while maintaining its water balance.
The commitment of the Bulgarian Prime Minister, Boyko Borisov, was to execute the project in record time, with that objective, the material selected by the technical managers has been a Class 500 Oriented PVC pipe from the Spanish manufacturer Molecor Tecnología, with a diameter of 630 mm and in a pressure range of 16, 20 and 25 bar.
The project officially started on January 29. At a rate of installation of several kilometers a day and with the technical assistance of Molecor during the design and installation phases, the project ended in record time, on March 13 the supply line from Sofia to Pernik was already installed.
From a technical point of view and taking into account the urgency of the installation, the Molecor Oriented PVC TOM® pipes met with the very high requirements of this project, which included the manufacturing and supply capacity, at the required rate of five teams simultaneous installation, to complete the works in the indicated time of 37 days.
Trucks with 630 mm diameter pipes, to be installed on-site by Montagi AD, were progressively sent from Molecor's facilities, up to a total of 300, which satisfactorily met these project needs.
The pipes should also be easy of handle, store, distribute and assemble on-site; characteristics for which, the lightness of the Molecor TOM® pipes, whose weight is less than half of PVC and PE pipes, and between six and twelve times less per linear meter than the cast iron pipes of an equivalent nominal external diameter, has been essential during the development of the project.
This same lightness contributed to the connection system of the pipes, which is carried out by inserting the male end of the pipe into the socket of another in which an elastic joint is placed, and to fast and effective installation, with minimal possibilities of failures during their connection. In addition, the Molecor connection system guarantees total tightness of the joints, thanks to this elastic joint, made up of a polypropylene ring and a synthetic rubber lip that become an integral part of the pipe, preventing it from moving or from being rolled up during installation, thus eliminating losses from the former Pernik supply network, estimated at over 75%.
On the other hand, the installed pipeline, thanks to its higher hydraulic capacity, between 15% and 40% compared to pipes of other materials with the same external diameter, is capable of transporting a higher flow with optimal hydraulic behavior and a minimum pressure drop that leads to significant energy savings during pumping. This pumping, on the Sofia - Pernik line, involves the drive from the catchment to a tank located at a height of 160 m; tank from which the main connection to the supply network to Pernik is supplied by gravity.
The TOM® Oriented PVC pipes should also have excellent behavior against water hammer, sudden variations in flow and pressure, reducing and almost eliminating the possibility of breaks in the openings and closings of the network and in the starts of the supply, something that contributes to protect all the elements of the network in a highly efficient way.
The absence of maintenance costs was also an important point in the new supply line to the city of Pernik, a characteristic that TOM® pipes also comply with. PVC-O is immune to corrosion and chemical substances found in nature, therefore it is non-degradable. Likewise, these pipes are immune to attacks by micro and macro-organisms found in nature. In addition, they do not need any type of special coating protection, which results in important cost savings.
The long service life of the TOM® PVC-O pipes in the long term, over 75 years, implies enormous resource savings in the long term, thus optimizing the investment made. In addition, these pipes, certified in more than 10 countries and with several health certificates, guarantee the total quality of the transported water for consumption by the population of Pernik.
Molecor has also provided technical assistance during the design and installation phases with its own local staff and with Bulgaria's leading distribution partner, HTI Bulgaria, in addition to providing a very competitive final cost of installed pipe compared to alternative solutions.
Once the installation of the new supply line was completed, on March 13, and after having carried out all the necessary tests, the project was officially inaugurated by the Bulgarian Prime Minister, Boyko Borisov, on March 23, 2020. A project that has, once again demonstrated, that the TOM® PVC-O pipes of Molecor are the best solution for the conveyance of water under pressure.