AmortiZATION OF MILLIONS
174-km SEWER SYSTEM FOR Nowy Sącz
Katarzyna Polanska-Zorychta, Steinzeug-Keramo Sp. z o.o.
Sądeckie Wodociągi Sp. z o.o., the water-supply and wastewater-disposal company for the district town of Nowy Sącz (administrative district of Małopolskim, in southern Poland) and its 83,000 citizens put out a public tender for the construction of a sewer system with an overall length of 174 km. The plans for this major project took from 2007 until 2011 to finalize. So far, 113.52 km of the system have been completed, by far the greatest part using the open trench method.
River crossed, obstacles overcome
The construction of a sewer system of these dimensions in many cases involves numerous difficulties, and this was no different in the case of Nowy Sącz: a 151-m tunnel had to be dug beneath the Poprad river, while at various other places along the planned route considerable top covers and obstacles had to be overcome. Microtunnelling was the method considered most suited for crossing the river.
The local subsoil conditions posed no major problems for the open trench installation and microtunnelling operations: alternating strata of sand, loam, clay sand, gravel, and clay proved no hindrance to good progress at depths ranging between one and seven meters. The open trench installation work (including house connections with the corresponding fittings) was done with vitrified-clay pipes of DN 150 to DN 600, while the DN 600 pipes used to cross the river using the microtunnelling method were made of composite vitrified clay. Sections with substantial top cover and other obstacles were surmounted using vitrified-clay jacking pipes in a variety of diameters. The exact figures for the individual pipe dimensions that were used are summarized in the table below.
EU funds well invested
The decision to use vitrified-clay pipe systems for this construction project was made with a clear vision into the future, in terms of amortization. The decision-makers focussed special attention on the chemical, physical, and mechanical resilience, the resistance to abrasion, and the watertightness of the raw material, vitrified clay. After all, the overall project involved the investment of EU funds in the amount of 24,874,431.95 euros as well as 40,898,817.28 euros allocated by the local authorities themselves.
Client: Sądeckie Wodociągi Sp. z o.o. , Nowy Sącz | Planning: Prac. Proj. Sieci i Instal. Sanit. ISAN, Nowy Sącz; Biuro Projektowe Ekosystem, Kraków; Pracownia Projektowa Marcin Golonka, Nowy Sącz; Biprokom Kraków S.A., Kraków | Construction:MOSTOSTAL Warszawa S.A., Warszawa; MACHNIK, Krynica Zdrój; INTER-BUD, Kraków; ABM SOLID, Tarnów; FEWATERM Sp. z o.o. S.K., Gromnik | Construction-materials supplier: Centrum Materiałów Budowlanych RAMEX Sp. z o.o. S.K.A., Nowy Sącz; HTI BP Sp. z o.o. POŁUDNIE Sp.K., Kraków